Invasion Pearl Harbor Rulebook

Table of Contents

Table of Contents

• 1.0 Introduction
  • 1.1
  • 1.2 Game Scales
  • 1.3 Counterfactual Background
  • 1.4 Opposing Forces
  • 1.5 Seating
• 2.0 Components
  • 2.1
  • 2.2 The Game Map
  • 2.3 The Counters
  • 2.4 Sample Ground & Air Units
  • 2.5 Sides
  • 2.6 Unit Identifications
  • 2.7 Unit Types
  • 2.8 Ground Unit Size
  • 2.9 Attack & Defense Factors
  • 2.10 Movement Factors (MF) & Static Units
  • 2.11 Steps
  • 2.12 Organizational Affiliations
• 3.0 Set Up & Hex Control
  • 3.1
  • 3.2 Japanese Beachhead Selection
  • 3.3 US Set Up
  • 3.4 Japanese Set Up
  • 3.5
  • 3.6 Hex Control
• 4.0 How to Win
  • 4.1
  • 4.2 Japanese Victory
  • 4.3 US Victory
  • 4.4 Victory Points
  • 4.5 Ford Island & Battleship Row VP
  • 4.6 Initial Japanese VP
  • 4.7 Ship-Loss VP
  • 4.8 VP Gain & Loss
• 5.0 Sequence of Play
  • 5.1
  • 5.2 Game Turn Sequence Outline
  • 5.3 Carrier Warfare Phases
  • 5.4 US Submarine Strike Phases
  • 5.5 Japanese Landing Phases
  • 5.6 US Sub-Command Chit-Pull Phases
  • 5.7 Japanese Movement & Combat Phases
  • 5.8 Ending a Game Turn
  • 5.9 Night Turns
  • 5.10 Unique Game Turn 1 Sequence
• 6.0 Stacking & Fog of War
  • 6.1
  • 6.2 Japanese Stacking
  • 6.3 Battleship Row Stacking
  • 6.4 USMC Stacking
  • 6.5 US Army Stacking
  • 6.6 US Fort Garrisons
  • 6.7 Free Stacking Units
  • 6.8 Fog of War
• 7.0 Naval Warfare & Airpower
  • 7.1 Japanese BB Combat Support
  • 7.2 Carrier Warfare Phases
  • 7.3 Ship Disposition Segment
  • 7.4 IJN Finds US
  • 7.5 USN Finds IJN
  • 7.6 Mutual Discovery
  • 7.7 No Carrier Combat
  • 7.8 Sunk Ships & Damaged Ships
  • 7.9 No Close-In CV or BB
  • 7.10 Ships & Aircraft After the Carrier Combat Phase
  • 7.11 US Submarine Attack
• 8.0 Japanese Landings
  • 8.1
  • 8.2
  • 8.3
  • 8.4
  • 8.5 Landing Phase Procedure
• 9.0 Movement
  • 9.1
  • 9.2 Movement Strictures
  • 9.3 No Minimum Movement Capability
  • 9.4 Stack Movement
  • 9.5 Splitting Stacks
  • 9.6 US Stack MF
  • 9.7 Enemy Units
  • 9.8 Terrain Costs for Movement
  • 9.9 Roads
  • 9.10 All-Water Hexsides
  • 9.11 No Off-Map Moves
  • 9.12 US Sub-Command Strictures
• 10.0 Combat
  • 10.1
  • 10.2 Procedure
  • 10.3 Attack Limits
  • 10.4 Japanese Attack Momentum
  • 10.5 Multi-Unit & Multi-Hex Combat
  • 10.6 Defender Commitment & Integrity
  • 10.7 Combat Strength Unity
  • 10.8 Terrain Effects on Combat
  • 10.9 Combat Results
  • 10.10 Advance After Combat
  • 10.11 Odds Limits & Odds Reductions
  • 10.12 Concentric Attack
• 11.0 Ford Island & Battleship Row
  • 11.1
  • 11.2 Ford Island Combat & Movement
  • 11.3 BB Row Attacking
  • 11.4 BB Row Defending
• 12.0 Banzai & Night Turns
  • 12.1 Banzai!
  • 12.2
  • 12.3
  • 12.4

1.0 Introduction

1.1

Invasion Pearl Harbor: What If the Japanese Invaded on 7 December 1941 (IPH for short), is a low-to-intermediate complexity, strategic/operational-level, alternative history wargame of the campaign that could've resulted had the Japanese decided to launch an amphibious invasion of Oahu at the same time as their historic air raid. The game is intended for two players, one commanding the Japanese, and the other commanding the US forces. The game system is focused so as to present the ground-commanders' views of the campaign. Aero-naval operations — though certainly still important in play — are therefore presented more abstractly than would be the case in a design centered on those aspects of the campaign.

1.2 Game Scales

Each hex on the map equals one mile (1.62 km) from side to opposite side. Each game turn represents about four hours of daylight or an entire night. Playing pieces represent ground units of approximately company size, or individual aircraft carriers or battleships, or enough aircraft sorties (about two to three dozen) needed to affect battlefield events at this scale.

1.3 Counterfactual Background

In keeping with the practices of good alternative history, we've kept to a minimum the changes we believe would've been necessary to the historic timeline in order to have brought about the situation depicted here. That is, the single counterfactual assumption underlying the game is Adm. Yamamoto decided to back the plan he scrapped historically in September 1941. That plan had called for an amphibious invasion, conducted by about two regiments, to land on Oahu at the same time as the air attacks were begun. The further supposition then is, the Japanese, once ashore, would've had no more than about three days in which to achieve their now more ambitious goal: either secure the whole island or at least fight their way across enough of it — while thoroughly wrecking facilities as they came to them — to ensure the American recovery would be delayed as long as possible. The three-day limit is due to the fact that, by the end of that period, the Japanese carrier strike group would had to have withdrawn and the ground force's initial load of combat supply would be used up.

1.4 Opposing Forces

The Japanese air and naval forces in the game are taken from the historic order of battle for those types of units. Likewise, the American ground order of battle is what was there historically. The units making up the US 24th and 25th Infantry Divisions; however, are represented simply as so many rifle companies. That's because those two divisions had only been established on 1 October 1941 (the split halves of the long-static "Hawaiian Infantry Division), and essentially still existed only as large masses of semi-trained personnel.

Concerning the Japanese ground force, the assumption is the largest units they could've brought to the island without disrupting the rest of their historic offensives would've consisted of no more than one SNLF unit and one army regiment. Further, in order to get even that relatively small number of men to Hawaii on fast destroyer-transports, the Japanese would likely have had to leave behind their heavy equipment. Thus the invaders also come ashore as just so many riflemen.

1.5 Seating

The Japanese player should sit off the north side of the map, facing south. The US player should sit off the south side of the map, facing north.

2.0 Components

2.1

The components to a complete game of IPH include these rules, the mapsheet and 176 die-cut counters (also called "units" and "unit counters"). Players must provide themselves with a standard six-sided die to resolve combat and other probabilistic events that occur during play.

2.2 The Game Map

The map represents the militarily significant terrain found across Oahu in 1941 when portrayed at this scale. A hexagonal ("hex") grid is printed over it to regulate unit placement and movement similar to the way squares are used in Chess and Checkers. A unit is always in only hex at any one instant. Each hex contains natural and/or manmade terrain features that may affect movement and combat. The map's terrain representations have been altered slightly from their exact real-world configurations in order to make them conform to the hex-grid. The terrain relationships from hex to hex are, however, accurate to the degree necessary to present players with the same space/time dilemmas that would've been faced by their real-world counterparts if this campaign had actually been waged. Each hex on the map has a unique four-digit number printed in it. They're provided to help you find specific locations referred to in the rules (for example, Ford Island is in hex 3020), and to allow you to record unit positions if a match has to be interrupted and taken down before it can be completed. Also note the one-hex gap in the city of Honolulu is deliberate, and reflects the density of construction of that time.

2.3 The Counters

There are 176 counters in the game, most of which represent combat units; others are provided as memory aids and informational markers. Carefully punch out the counters. Trimming the "dog ears" from their corners with a fingernail clipper greatly facilitates handling and stacking during play and enhances their appearance. Each combat unit-counter displays several types of information: nationality, type, combat strength, historic identification and higher organizational affiliation.

2.4 Sample Ground & Air Units

This unit is a Japanese SNLF company. When at full-strength, it has attack and defense factors of "3" and a movement factor of "7."

Unit Size Unit Type Organizational Affiliation Attack Factor Defense Factor Movement Factor

Ground Support Shift Anti-Ship Hit Number

2.5 Sides

A unit's nationality, and therefore its "side," is indicated by its background color.

The US Side

• 24th Infantry Division — green
• 25th Infantry Division — olive drab
• Marine Corps — blue
• Fort Garrisons — dark gray
• Aircraft Carriers & Aircraft — sky blue
• Battleship Row Vessels — light gray

The Japanese Side

• SNLF — red
• Army Regiment — orange
• Ships & Aircraft — white

2.6 Unit Identifications

Each ground unit is further identified by a number, or by the abbreviated name of its real-world counterpart. Those abbreviations are as follows.

Japanese Abbreviations

• BB — Battleship
• IJA — Imperial Japanese Army
• Kiri — Kirishima
• SNLF — Special Naval Landing Force

US Abbreviations

• BB — Battleship
• PH — Pearl Harbor Defense Battalion
• USMC — United State Marine Corps

2.7 Unit Types

Units are also distinguished by the major combat-arms-type contained within them.

• Imperial Japanese Army Infantry
• Japanese SNLF Infantry
• Japanese Carrier-Based Aircraft
• US Army Infantry
• USMC Infantry
• US Fort Garrisons
• US Navy Carrier-Based Aircraft
• US Army Land-Based Aircraft

2.8 Ground Unit Size

Each individual ground unit in the game on both sides is a company or ad hoc company equivalent.

2.9 Attack & Defense Factors

These numbers are a measure of each unit's relative ability to attack and defend (see section 10.0).

2.10 Movement Factors (MF) & Static Units

The movement factor of all Japanese SNLF and IJA units is seven, and that number is printed in the lower-right corner of those units. The movement factors of US Army and Marine units aren't printed on their counters; they have a question mark printed there in its place. The MF of those units are determined, on a move by move basis, by a die roll and the calendar date of the game turn being played. That is, on game turns of 7 December, the movement factor of each US unit or stack is determined at the start of its move by rolling a six-sided die ("1d6") and then subtracting one from that result, to get a movement factor for that turn of from zero to five. For game turns during 8 December, that formula is changed to 1d6 (that is, no subtraction is made from rolled results). For 9 December game turns the formula is "1d6+1," yielding possible MF of two through seven. (All that is shown as a reminder on the Turn Record Track printed on the mapsheet. See section 9.0 for more details.)

Also note that Japanese Beachhead markers, the US Battleship Row counter, and all US fort garrisons are static: they never move, once initially placed on the map, except possibly to go into the dead pile. The movement of ships-at-sea and aircraft is explained in section 7.0.

2.11 Steps

All Japanese ground units in the game contain two "strength steps" (also simply called "steps"). That's an arbitrary term used to express the ability of a unit to absorb certain amounts of combat losses before ceasing to be an effective formation. Those units with combat factors on only one side of their counter are "one-step" units; those with combat factors on both sides of a single counter are "two-step" units. All US Army ground units are one-step units; all USMC units are two-step units.

If a two-step unit suffers a step loss, it's flipped over so its reduced side (with the lower combat values) shows. If a one-step unit, or a two-stepper that had already been reduced, takes a step loss, it's removed from the map (eliminated) and placed in the "dead pile." All Japanese and USMC units start the game at their two-step strength. No unit may ever give or loan a step to another. (The concept of steps doesn't apply to aircraft or ship units; see section 7.0.)

2.12 Organizational Affiliations

The US forces on Oahu are divided into four sub-commands: 24th Infantry Division, 25th Infantry Division, the USMC, and Battleship Row. The invading Japanese ground force is divided into two sub-commands: the SNLF and the IJA. For the importance of those distinctions, see 9.12 and 9.13.

2.13 Other Markers & Counters

The following counters are also included in the game as information markers and memory aids. Their functions are explained in the relevant portions of the rules that follow.

• Japanese Victory Point Marker (see section 4.0)
• Japanese Control Markers (see section 4.0)
• US Sub-Command Move / Fight Chits (see section 5.0)
• Game Turn Marker (see section 5.0)
• Japanese Beachhead Marker (see section 8.0)
• Japanese No Move or Attack Marker (see section 8.0)

3.0 Set Up & Hex Control

3.1

The game starts just prior to the first Japanese stepping ashore on Oahu; so there are only US units on the map at the very start of play.

3.2 Japanese Beachhead Selection

Prior to either player placing any units on the map, the Japanese player must secretly select and write down the central hex of his three-hex beachhead. (See section 8.0 for more details.) He may select any one hex from the North Coast Invasion Area, which runs along that coast from 1632 to 1225, inclusive; or he may select any one hex from the East Coast Invasion Area, which runs along that coast from 1220 to 3803, inclusive; or he may select any one hex from the Kaneohe Bay Invasion Area, which runs along the coast from 2311 to 2806, inclusive. He should write down the hex on a piece of paper, and then set it aside within easy reach, being careful not to let the US player see the hex number. The hex number written down is the central hex of what will actually be a three-hex-line of contiguous hexes. So, for example, if the Japanese player wanted to come ashore in hexes 1630, 1631 and 1632, the hex he'd write down would be 1631. No unit may come ashore outside of one of the areas. Similarly, at the boundary between the North and Kaneohe Bay areas, the hex selection must be made so the entire three-hex landing area is entirely within one or the other area.

3.3 US Set Up

The US player sets up first. He should first place all seven of his "Sub-Command Chits" ("24th Fight," 24th Move," "25th Fight," etc.) into any convenient, large-mouthed, opaque container, such as a coffee mug or cereal bowl, and then set that container off to the side within easy reach. He should place his two aircraft carrier (CV) and their aircraft units in the "USN Ships Distant" box, while placing his single US Army aircraft unit off to the side within easy reach. He should next place the Battleship Row counter in hex 3020. Then he should place one fort garrison counter in each of those seven hexes (pentagonal symbols).

He then places all 37 units of the 24th Infantry Division within four hexes of either/both Schofield Barracks hexes (2125 & 2225). Count out from the barracks hexes; don't count the barracks hexes themselves. For example, hex 1727 is four hexes from 2125. These units may be placed singly and/or in stacks of up to four per hex. Note though, that at least two units must start in both barracks hexes.

Next, he places all 37 units of the 25th Infantry Division in any non-coastal hexes in rows 28xx and south, inclusive. The maximum stacking limit for these units is three per hex.

He should then set up the four USMC defense battalions, no more than one per hex, within four hexes of Pearl City (2821) and/or Ewa (3225) and/or the Marine Base (3327). These units may not stack with each other or with any 25th Infantry Division units.

3.4 Japanese Set Up

While the US player is setting up, the Japanese player should simply sort his units, within easy reach off to the side of the map, into eight piles according to the following categories: the SNLF, the IJA infantry regiment, the two battleships (BB), the six aircraft carriers (CV), the six aircraft counters, the control markers (flags), the three Beachhead markers, and the three No Move or Attack markers. He should place both Victory Point (VP) markers in the Zero ("0") box of that track on the mapsheet, and put the Game Turn marker in first box on that track on the mapsheet.

3.5

When the US player announces he's completed his side's set up, the Japanese player should reveal the hex number he wrote down earlier. He should then deploy all three of the Japanese Beachhead markers such that the hex written down contains one, along with the hexes on either side of it. For example, if the Japanese player had written "1631," a beachhead marker would go into that hex along with one in 1630 and another in 1632. The Japanese player should then also record his first victory points (see 4.6), using the marker-counters provided, on the VP track printed on the mapsheet. With all that done, the game is ready to begin with the Japanese player taking his first Landing Phase (see sections 5.0 and 8.0).

3.6 Hex Control

The idea of which side "controls" certain hexes on the map is important for purposes of reckoning victory (see next section). At the start of Game Turn 1, the US player controls all hexes of Oahu other than the three in which the Japanese Beachhead markers are located. The Japanese player takes control of other hexes on the map the instant one or more of his ground units enter (or move through) it. Similarly, the US player may take back control of a hex lost earlier to the Japanese by moving one or more of his units back into (or through) it. That back-and-forth process may take place in any given hex any number of times throughout the game.

Note, however, the "control status" of a hex is actually only meaningful in play if it yields victory points (see next section). Japanese control markers (the flags) are provided for use on the map as mnemonic aids. Also note neither player may take/retake control of hex by deploying an aircraft unit into it; ground units are required.

4.0 How to Win

4.1

The overall burden of attack is on the Japanese player, as he tries to overrun as much of Oahu as possible within three days. His success in that endeavor is measured in terms of victory points (VP), which he accrues for gaining control of certain hexes and/or by sinking US aircraft carriers, and all the while preserving as much as possible of his own aero-naval strength.

4.2 Japanese Victory

If, at any time prior to the end of Game Turn 11 (Dec. 9, Evening), the Japanese VP total reaches or exceeds 22 VP, play stops immediately and that player is declared the winner. Note that only the Japanese player accrues (and possibly loses) VP; there are no US VP. The Japanese player should keep a running and open total of his VP on the track printed on the mapsheet.

4.3 US Victory

If, by the end of Game Turn 11, the Japanese player has failed to achieve a victory as described above, the US player is declared to have won the game at that time. In addition, if the Japanese VP total at any time drops to zero or below, play stops and the US player is immediately declared the victor. Even further, play also stops and the US player is immediately declared the victor, if, at any instant, there are no longer any Japanese beachhead markers deployed on Oahu (see section 8.0).

4.4 Victory Points

Each hex containing manmade terrain — other than airfields — gives the Japanese player one VP as soon as he gains control of it. Those one-point manmade terrain types include, as identified on the Terrain Effects Chart printed on the mapsheet: military installation hexes, city hexes, fortification hexes, and oil storage hexes. Each airfield hex yields two VP to the Japanese player when he gains control of it.

4.5 Ford Island & Battleship Row VP

In relation to its VP yield, note the Ford Island aero-naval facility (hex 3020) contains both an airfield and Battleship Row. The destruction of the BB Row counter has a separate, additional VP yield to that of the two-VP airfield in that same hex. That is, if the BB row counter is eliminated on any December 7 game turn, the Japanese player immediately rolls a die, subtracts one from that result, and awards himself that number of VP (0-5). If the BB row counter were destroyed on any December 8 game turn, the procedure would be the same except he'd subtract two from his die roll result (0-4). On December 9 the formula would be to subtract three (0-3). Note the Japanese player may never actually lose VP for destroying the BB Row counter.

4.6 Initial Japanese VP

The Japanese player always starts Game Turn 1 with at least three VP, one for each of his three beachhead markers. Depending on the hexes in which he lands, he might get more initial VP. For example, if the Japanese came ashore in hexes 1630, 1631 and 1632, he'd start the game with four VP. The additional point would be for his seizure of the city of Halei-wa in hex 1630.

4.7 Ship-Loss VP

Every time the Japanese player sinks a US aircraft carrier, he should immediately award himself three VP. If he damages a US carrier, his VP award is one VP. Similarly, whenever the Japanese player has one of his own side's carriers sunk or damaged, he must deduct three or one VP, respectively, from his VP total. If a Japanese battleship is sunk or damaged, the VP debit is two or one VP, respectively. For more details on naval combat, see section 7.0.

4.8 VP Gain & Loss

Once the BB Row counter has been eliminated, the VP gained by the Japanese player for accomplishing that are permanently his. That is, even if the US player regained control of Ford Island, the VP for eliminating BB Row would still remain in the Japanese VP total. The same holds true for all VP debits and awards for ships lost or damaged at sea: they may never be recouped in any way. The opposite is true, though, for VP awards for Japanese hex control on Oahu. That is, for example, if the US player retook Ford Island after it had earlier been lost to the Japanese, two VP (for its airfield) would immediately be debited from the overall Japanese VP total. The Japanese player may also lose VP for losing control of one or more of his beachhead hexes. A given hex's VP award may go in and out of the Japanese VP total any number of times per game.

5.0 Sequence of Play

5.1

Every game turn of IPH is divided into a series of sequenced steps (or "phases"). That complete sequence makes up one "game turn" (GT), of which there are a maximum of 11 in an entire game. At the very end of every completed game turn, move forward the Game Turn marker one box on the Game Turn Record Track. The game turn sequence is presented below in outline.

5.2 Game Turn Sequence Outline

Note that the sequence below is followed in every game turn except the first, which has its own unique, truncated sequence (see 5.10 below).

I. Carrier Warfare Phase (only GT5 & GT9) A. Ship Disposition Segment B. Carrier Combat Segment II. US Submarine Attack Phase (only GT5 through GT11) III. Japanese Landing Phase IV. US Sub-Command Chit-Pull Phase* V. US Sub-Command Chit-Pull Phase* VI. US Sub-Command Chit-Pull Phase* VII. US Sub-Command Chit-Pull Phase*

*May be preceded or followed by the Japanese Movement or Combat Phase, to the limit of one of each such Japanese phase being executed per game turn. See 5.7 for details.

5.3 Carrier Warfare Phases

Occur only at the start of Game Turn 5 and 9. On all other turns they're simply and fully skipped. See 7.2 through 7.10 for more details.

5.4 US Submarine Strike Phases

Occur (potentially) only at the start of Game Turns 5 through 11. Even then, they're skipped if there are no Japanese ships "close in" during any of those game turns. See 7.11 for more details.

5.5 Japanese Landing Phases

Must be taken — and the maximum number possible of ground units must be brought ashore during each one — until such time as there are no longer any ground units left to land. See section 8.0 for more details.

5.6 US Sub-Command Chit-Pull Phases

Every US sub-command except BB Row has two chits, one printed "Fight" and the other "Move" (see 2.12). The Battleship Row sub-command only has a single "Fight" chit because it's static and never moves except possibly to go into the dead pile. Starting with Step IV of Game Turn 2, and every game turn thereafter, the US player randomly (without first looking) picks one sub-command chit from the opaque container into which he placed all of them during set up (see 3.3).

Whatever chit he pulls defines the next phase — movement or combat — and for which sub-command — he must then execute. For example, if he pulled the "24th Move" chit, he would then execute a movement phase for the units of that division. When a given chit has been pulled from the container, set it aside until the start of the next game turn, when all of them are put back into the container. No chit may make more than one appearance per game turn. When/if all of a given sub-command's units have been eliminated, permanently remove that sub-command's chits from the container.

5.7 Japanese Movement & Combat Phases

At the completion of any US Sub-Command Movement or Combat Phase, the Japanese player may interrupt the US player by announcing he (the Japanese player) will take his movement or combat phase at that time. Alternatively, the Japanese player may choose to announce, just prior to the US player reaching into the container to pull a chit — even if it's for the first time that game turn — that he (the Japanese player) will take his movement or combat phase at that time.

Note, once the US player has pulled a chit and begun to execute a phase, the Japanese player may not interrupt its execution; he may only do so prior to and/or after the start/end of a US Sub-Command Movement or Combat Phase.

When he interrupts the US Sub-Command sequence, the Japanese player may decide to execute just one of his phases, or he may decide to execute both, in either order, at that time.

Also note, even though the Japanese ground force is divided into two sub-commands (the IJA and SNLF), he still conducts (under certain restrictions, see 9.13) only one movement and combat phase per game turn. There may never be more (or less) than one Japanese Movement Phase per game turn, and there may never be more (or less) than one Japanese Combat Phase per game turn — and both his sub-commands participate simultaneously in both those phases.

5.8 Ending a Game Turn

Repeat the process described above in 5.6 and 5.7 until there are no more US Sub-Command chits left in the container. At that time, if the Japanese player still hasn't taken one or both of his phases (movement and combat), he does so at that time (again, in the order of his choice if both phases remain to be taken). Once that's been done, place all the US Sub-command chits back into their container and begin a new game turn.

5.9 Night Turns

Game Turns 4 and 8 are night game turns. During night game turns the following special rules apply. First, remove all US Sub-Command "Fight" chits from the container prior to pulling the first chit for those turns. Second, there are no aircraft operations during those turns. Third, the only possible combat will be in the form of Japanese night attacks (see 12.4) and US submarine attack (see 7.11).

5.10 Unique Game Turn 1 Sequence

During Game Turn 1, the Japanese player takes his landing phase, followed by his movement phase and combat phases (or his combat phase and then his movement phases, his choice). That done, the first game turn is over. The second game turn is then immediately begun with its Japanese Landing Phase. There are never any aerial or carrier operations during Game Turn 1. Both of the Japanese battleships are automatically considered "close in" during Game Turn 1; so they should be moved into the "IJN Ships Close In" box at the start of the turn.

6.0 Stacking & Fog of War

6.1

"Stacking" is the term used to describe the piling of more than one friendly unit in the same hex at the same time. Opposing units never stack together. Stacking rules are in effect all through every game turn.

6.2 Japanese Stacking

The general rule is, the Japanese player may stack up to four ground units in every hex on the map. Note, though, that IJA and SNLF units may generally not be stacked together. The exception is, units of both sub-commands may always stack together, up to the normal four-high limit, in beachhead hexes. Also note Japanese Beachhead counters don't count for stacking.

6.3 Battleship Row Stacking

The static BB Row unit may never be stacked with any other US ground unit.

6.4 USMC Stacking

The four USMC defense battalions may never stack with each other or with any other US ground units other than fort garrisons. A maximum of one USMC battalion may stack with any fort garrison counter in a fortification hex.

6.5 US Army Stacking

The US player may stack up to four units from either of his infantry divisions (24th and 25th) per hex. Units from the two divisions may never stack with USMC units or with the BB Row counter. Units from the two divisions may stack together, up to the normal four-high limit, only if they're stacked in a fortification hex.

6.6 US Fort Garrisons

Are static and don't count for stacking, though there will never be more than one of them per hex. They never attack or move (except to go into the dead pile), and they're not considered a separate sub-command. If units from both infantry divisions are stacked in the same fortification with a garrison counter, those infantry units may still only attack by specific sub-command chit pull, not as a new artificially unified sub-command. If the US player loses a fort garrison counter, and later retakes that hex, the garrison counter doesn't reappear. In such cases, though, the normal defensive combat bonuses would still be available. See 10.14 for more details.

6.7 Free Stacking Units

None of the counters shown in rule 2.13 have any stacking value, and they may be added, as needed, to any stacks in accordance with the rules governing their specific uses. Also note the stacking rules don't apply to aircraft or ships at sea (see section 7.0 for details).

6.8 Fog of War

The Japanese player is always free to examine all stacks of US units on Oahu. The US player may only examine Japanese stacks when he declares attacks against them (and he's not allowed to call off an attack once he's made such an examination).

7.0 Naval Warfare & Airpower

7.1 Japanese BB Combat Support

The two-vessel (Hiei & Kirishima) Japanese "battleship division" is available for that player's use starting with Game Turn 1. Both those ships have combat factors of six. Whenever one or both are in the "IJN Ships Close In" box, it/they may contribute those factors — alone or together, day or night, on offense or defense, once each per game turn — to any battle in which one or more friendly ground units are involved anywhere on Oahu. They never make their own separate attacks; nor may either one split its combat factor between more than one battle, and they may never be given up to satisfy combat losses in battles they support. They may only be damaged or sunk by US aerial attack (see 7.5ff below). The BB may never attack US CV, though the BB may be attacked by US carrier-based aircraft (see 7.5 below).

7.2 Carrier Warfare Phases

There is no activity by either side's airplanes or aircraft carriers until the start of Game Turn 5. On that game turn, and then again as the first phase of Game Turn 9, the Carrier Warfare Phase is added to the turn sequence, for a total of two such phases per game.

7.3 Ship Disposition Segment

First, while the US player temporarily turns away from the map, the Japanese player should take all his ship counters, both CV and BB, and place them, in any combinations he wants, in either or both the "IJN Ships Close In" and the "IJN Ships Distant" holding boxes printed on the mapsheet. He should also place one aircraft unit beneath each CV counter. He should then cover both holding boxes with note cards or a sheet of paper.

When all that's done, the US player makes a similar disposition of his own side's two CV and two naval aircraft units in the USN holding boxes. The third US aircraft unit is land-based and is identified as "US Army"; he should place it in the "US Aircraft Available Box." (The Japanese player need not turn away when the US player makes his ship and aircraft dispositions.)

When the US player announces he's finished with his side's dispositions, the Japanese player should lift the cover from his own side's holding boxes. If both players have one or more CV in their "Ships Close In" boxes, the Japanese player rolls a die and both players consult the (identical) Carrier Warfare Tables printed on the mapsheet. The results on those tables are explained in the following four rules.

7.4 IJN Finds US

If this is the result, there will immediately be a Japanese aerial attack against the US carrier(s) in the "USN Ships Close-In" box, but there won't be any corresponding US aerial attack against any Japanese CV. To resolve his attack, the Japanese player should roll a die for each of the aircraft counters accompanying (one each) his "Close-In" carriers. If both US carriers are in the "USN Ships Close-In" box, prior to making any air-attack rolls, the Japanese player should take his plane counters and line them up against one or both US CV, however he desires. Once a plane counter has been committed against a given US CV, it may not be reallocated during that segment. If the roll for an attacking Japanese airplane is less than or equal to its "hit number" of "3," it has scored a hit and should immediately have a second die rolled for it. If that second roll is odd, the hit US ship is sunk; if that second roll is even, the hit US ship is damaged. Attacking aircraft are never themselves destroyed by the ships they're attacking. There are no multi-round attacks. As soon as each attacking plane has had one (or two) die rolls made for it, return it to a friendly aircraft carrier in the its own side's "Close-In" box. Note the carrier-based plane counters are 'generic'; you needn't keep track of which one 'belongs' to each carrier.

7.5 USN Finds IJN

If this is the result, there will immediately be a US aerial attack against the Japanese carrier(s), and or battleship(s), in the "IJN Ships Close-In" box, but there won't be any corresponding Japanese aerial attack against any US CV. The procedure is the same as given above in 7.4, except as follows.

1. The initial "hit number" of US carrier-based aircraft is always four.
2. The US hit/damaged roll is the same as the Japanese.
3. US Army aircraft never attack Japanese ships.
4. If only IJN CV is/are close-in, the US player may pick his target(s) exactly as the Japanese player. If, however, one or more BB are close-in along with one or more IJN CV, the US player simply makes his to-hit die rolls (one per attacking plane) without assigning any specific target ships to them. If one or more hits results, place all close-in IJN ships in a large-mouthed opaque container and, without looking, have the US player pull out the number of ships corresponding to his number of hits (one or two). That done, he then makes an odd/even, sunk/damaged second die roll for each hit ship (one or two) that he just pulled from the container.

7.6 Mutual Discovery

If this is the result, first run through the procedure given above in 7.4, and then run through the procedure given in 7.5. Don't remove any sunk or damaged ships, though, until both the US and IJN attacks have both been resolved; they're considered to be taking place simultaneously.

7.7 No Carrier Combat

If this is the result, there is no Carrier Combat Segment that phase. Note, however, if one or more Japanese BB are close-in, and it/they give combat support to any ground battle that day (as described above in 7.1), the US player may then launch a carrier-based aircraft strike against it/them from any of his close-in CV. Also note, however, there may not be more than one such attack per day against a given BB, no matter how many ground battles that BB supports that day. Further note that participating in such BB strikes doesn't do away with any US air unit's ability to give combat support to US ground forces that same day.

7.8 Sunk Ships & Damaged Ships

A sunk or damaged ship is permanently removed from play. If the ship is a CV, one carrier-based aircraft counter is permanently removed along with it. Note that, in game-play terms, the only effective difference between a sunk and damaged ship is in the VP award or debit generated (see 4.7). Also note no separate VP award/debit is made for an aircraft counter accompanying its CV out of play; that total is part of the VP adjustment made for the CV.

7.9 No Close-In CV or BB

If, at the end of a Ship Disposition Segment, it's revealed one or both players doesn't have any aircraft carriers in the close-in boxes, there's no Carrier Combat Segment that game turn. If it's Game Turn 5, there can't possibly be any carrier combat until Game Turn 9; if it's Game Turn 9, there won't be any carrier combat for the rest of that game. Ships in "Distant" boxes, both CV and BB, may never attack or be attacked in any way. Exception: if one or both Japanese BB are close-in (but with no IJN CV also being close-in, and one or both US CV are close-in, the US player gets an automatic air attack against the BB(s).

7.10 Ships & Aircraft After the Carrier Combat Phase

If one or more close-in CV survives the Carrier Combat Segment, each of those ships' plane counters thereby also survive. In the case of Japanese aircraft counters, they're then available for use, no more than once per daylight game turn per counter, for either interdiction or combat support missions. US planes are only available (again, no more than once per daylight game turn per counter) for combat support. No carrier-based aircraft unit is ever removed from play except as described above in 7.4 and 7.5. After each Carrier Combat Segment, leave all surviving ships in the holding boxes until the next Carrier Warfare Phase or until the end of the game, whichever comes first. Leave plane counters in the holding boxes until needed for combat support or interdiction missions.

7.11 US Submarine Attack

This phase is the second phase of Game Turns 5 through 11, inclusive. If, at any of those times, one or more IJN ships is close-in, the US player rolls two dice (or one die twice). If that combined result is a three or an 11, a Japanese vessel has been hit by a US torpedo. If more than one Japanese ship is close-in, select it randomly as described in rule 7.5(4). Once randomly selected in that way, the second die roll of the hit ship is resolved as follows: 1 = sunk; 2-6 = damaged. Score normal VP in both cases. US submarine attack takes place at night as well as during daylight turns. Note, though, no more than one two-die hit check is made per game turn no matter how many IJN ships are actually close-in. Also note there is no US submarine counter in the game; it's all just resolved as die rolls.

7.12 Japanese Aircraft & Ground Combat Support

During the daylight game turns of December 8 and 9, once Phases I and II have been worked through as described above, surviving planes aboard close-in Japanese CV may be used by that player to give combat support to his ground force. Each aircraft may support one battle, offense or defense, per game turn anywhere on Oahu. The effect of each aircraft counter's participation is to generate a one-column odds shift on the Combat Results Table in favor of the Japanese. Note, however, the Japanese player may not commit more aircraft counters to a battle than he has ground units participating in that same battle. In any battle, the Japanese commitment of this kind of air support must be made as the first step after an attack has been declared by either player. Japanese aircraft flying combat support may not be aborted or destroyed in any way. Also see 10.4.

7.13 Japanese Interdiction of US Ground Movement

As an alternative to using his available aircraft units to provide ground combat support, the Japanese player may decide, on an aircraft counter by aircraft counter basis, to use some or all of his planes to interdict US ground movement. To do so, just prior to the US player making that side's first sub-command chit pull for a game turn, the Japanese player should set out — in any hexes on the island, but not more than one counter per hex — as many interdiction missions as he desires, with their "Interdiction" sides showing upward. Each such counter interdicts its own hex and the six hexes immediately around it. The effect of such interdiction on moving US units is that, when entering any interdicted hex, the movement cost for that entry is increased by one point. There is no additional effect for hexes being interdicted by more than one Japanese aircraft counter. An aircraft used for interdiction will not be available for combat support that same game turn, and vice versa. Note that US aircraft may not interfere with this mission, nor may they fly their own interdiction missions.

7.14 US Carrier-Based Ground Combat Support

At the start of every battle during the daylight game turns of December 8 and 9, immediately after the Japanese player has declared his use (or non-use) of ground combat support aircraft in it, the US player should roll a die for each of his carrier-based aircraft units in his side's close-in box. If the result for a rolled-for counter is six, that plane flies a ground combat support mission for that battle. The effect of each aircraft counter's participation is to generate a one-column odds shift on the Combat Results Table in favor of the US. A US aircraft once committed in this way can't be rolled for again that same game turn. The US player may never decline to make a die roll check for an available aircraft unit. One or both carrier-based aircraft counters may show up at the same battle, no matter the number US ground units participating. US aircraft flying combat support may not be aborted or destroyed in any way.

7.15 US Army Air Corps Ground Combat Support

The strictures governing the US of the single US Army aircraft counter for combat ground support are the same as for the use of the USN planes, except as follows. First, once the US player has lost control of all the airfields on the map, this counter is permanently removed from play — and that remains true even if the US player would later regain control of one or more of those airfields. Second, when making the availability die roll for this plane, add one to the rolled result for every airfield on the island that hasn't yet been under Japanese control and that doesn't have any Japanese ground unit or interdicting aircraft immediately adjacent to it (and/or above it) at the time of the roll.

8.0 Japanese Landings

8.1

Japanese ground units come ashore only during the Landing Phases of daylight game turns. They may only come ashore through the Beachhead markers that were deployed according to the rules given in section 3.0. Each Beachhead marker may facilitate the landing of up to four Japanese ground units, of one or both of that side's sub-commands, in each Landing Phase.

8.2

The Japanese player deliberately picks the units he will land in each beachhead hex in each landing phase. He must land every unit he can get ashore (within stacking limits) in each such phase; he may not hold back any eligible unit. Units of his two sub-commands may stack together — within the overall limit of four units — when in a hex with a Beachhead marker.

8.3

Beachhead markers have no stacking value (they stack for free), and each one has a defense factor and a step-strength of one. They never attack. A beachhead counter is permanently removed from play if its hex comes under US control. A Beachhead marker must be the last step given up by the Japanese player to satisfy combat loss requirements in its hex.

8.4

Japanese units defending in and/or immediately adjacent to Beachhead marker always get a one-column odds shift in their favor, in addition to all other applicable odds shifters (see section 10.0).

8.5 Landing Phase Procedure

The Japanese player should first 'load up' all his beachhead hexes with the maximum number of units he may land there that phase. He then rolls a die for each newly landed unit and consults the Landing Table printed on the mapsheet. Apply whichever die roll modifiers apply based on the date and the geography. (The 9 December modifier isn't cumulative with the 8 December modifier; it's one or the other.) Units stalled on the beach during their landing (final result on the Landing Table of a four or five) should be marked with a "No Move or Attack" counter. Remove those counters at the end of each game turn. Units that aren't stalled have their full movement and combat capabilities for use during that same game turn's Japanese Movement and Combat Phases (whenever they're actually declared). No unit is ever stalled for more than one game turn.

9.0 Movement

9.1

Every ground unit in the game has a "movement factor" (MF) as described in rule 2.10. That movement factor is the number of "movement points" (MP) available for the unit to use in moving across the map during its sub-command's movement phase every game turn.

9.2 Movement Strictures

MP may not be accumulated from turn to turn or phase to phase, nor may they be given or loaned from one unit to another. A player may move all, some, or none of his eligible units in each of his movement phases throughout the game, at his own discretion. Units that move aren't required to expend all their MP before stopping. The movement of each individual unit or stack must be completed before that of another is begun. A player may only change the position of an already moved unit or stack if his opponent agrees to allow it. Units move from hex to adjacent hex — no "skipping" of hexes is allowed — paying varied movement costs to do so, depending on the terrain in the hex being entered and along its hex sides. The movement of your units takes place only during your own movement phases; no enemy movement takes place during your movement phases.

9.3 No Minimum Movement Capability

A unit otherwise eligible to move must have sufficient MP available to pay all movement costs associated with entering any given hex. If that's not the case, it may not move.

9.4 Stack Movement

To move together as a stack, units must begin their sub-command's movement phase already stacked together. Units aren't required to move as a stack simply because they started the phase in the same hex. In such situations, those units might be moved together, individually, or in smaller sub-stacks.

9.5 Splitting Stacks

When moving a stack, you may halt it temporarily to allow a unit or sub-stack to split off and move away on a separate course. The units left behind in the original (or "parent") stack may then resume their own movement, even splitting off more sub-stacks and lone units if desired. Once you begin moving an entirely different parent stack, however, you may then no longer resume the movement of earlier, partially moved, stacks without your opponent's permission.

9.6 US Stack MF

When making a die roll to determined the MF of units in a stack, only one roll is made. That final result (as modified by the date; see 2.10) is the MF of that entire stack for that phase. That remains true even if the stack fully or partially splits up during the phase.

9.7 Enemy Units

It's not permitted for your units to enter hexes occupied by enemy ground units of any types.

9.8 Terrain Costs for Movement

Units pay different costs to enter each hex based on the terrain in that type of hex. With the exception of roads (see 9.9 below), only one terrain type exists in each hex on the map, as identified on the Terrain Effects Chart (TEC) printed on the mapsheet. Note that if a hex contains any amount of any terrain other than clear, that hex is considered to be of that non-clear type for movement and combat purposes. For example, hex 1740 is mountain hex, while hex 1939 is rough hex (mountain trumps rough).

Old Hands Note. All "manmade terrains" other than roads exist in hexes that are otherwise clear terrain.

9.9 Roads

Whenever a ground unit or stack is moving from road-hex to road-hex across a hexside traversed by that road, that force pays only one MP to do so, no matter what kind of terrain cost would otherwise be involved were the road not present.

9.10 All-Water Hexsides

Other than during the beachhead landings of Japanese units (see section 8.0), the only all-water hexsides on the map that may be moved and/or attacked across are those immediately surrounding Ford Island in hex 3020. See 11.2 for more details.

9.11 No Off-Map Moves

No ground unit once in play on the map may be moved off it in any way except to go into the dead pile.

9.12 US Sub-Command Strictures

The US player may never move or stack together units of different sub-commands — as identified in rule 2.12 — during a single movement phase. That stacking prohibition is in place — in hexes other than fortifications — all during the game turn. Neither may units of different sub-commands ever attack together. If units of the 24th and 25th Division sub-commands were stacked together in a fortification hex, only those units belonging to the currently activated sub-command could attack during that combat phase.

9.13 Japanese Sub-Command Strictures

The Japanese player nominally has two sub-commands, the IJA and the SNLF. There is considerably more coordination between them, however, than is the case with those of the US. That is, though IJA and SNLF units may generally not take part together in the same attack, they share the same single Japanese Combat Phase each game turn. The exception is, Japanese SNLF and IJA units stacked in beachhead hexes may attack from those hexes as if they belonged to the same organization. That remains true even if pure-stacked units — from one organization or the other, but not both — are also taking part in that attack from hexes outside the beachhead.

The Japanese player need not resolve all his IJA attacks before starting any of his SNLF attacks, and vice versa.

Similarly, IJA and SNLF units may move through each other's hexes during the single Japanese Movement Phase each game turn, as long as they're not inter-stacked once that phase is over (again, in hexes other than beachheads).

Japanese naval and aerial combat support may be assigned to both IJA and SNLF units without any restrictions beyond those given for their general use in section 7.0.

9.14 Honolulu & US MF

If all five Honolulu hexes come under the control of the Japanese — not necessarily even at the same time, just as long as all of them were, at one or more times during play, under that side's control — subtract one from all US MF rolls.

10.0 Combat

10.1

Combat potentially takes place during every combat phase of both sides within the strictures given in 9.12 and 9.13. Attacking is always voluntary; the mere presence of adjacent enemy units or stacks doesn't obligate either player to attack. The player whose combat phase it is, is termed the "attacker," and the other player is the "defender," no matter the general situation across the map.

10.2 Procedure

The attacker totals the combat strength of all the units attacking a given hex and compares that to the total combat strength of the defending units in the hex under attack. The comparison is expressed as a ratio between attacking and defending strength points (attacking strength points divided by defending strength points), and is simplified by rounding down to one of the odds ratios listed across the top of the Combat Results Table (CRT) printed on the mapsheet. For example, if 13 strength points were attacking four strength points, the combat odds ratio would be 3.25 to 1, rounded off (always in favor of the defender) to three to one (3:1).

The odds obtained in the calculations described above may be modified ("shifted") by the terrain in the defender's hex and around its perimeter, as well as other factors described below. All applicable combat modifiers are cumulative in their effect. That is, in every battle all applicable modifiers are determined and their effects taken into account before the "final odds" are determined and the die is rolled to get a combat result.

Having determined the final combat odds, the attacker rolls a die. The result indicates the line on the CRT that's cross-indexed within the column representing the combat odds. The intersection of line and column yields a combat result. That result should be immediately applied to the involved units before going on to resolve any other combat. Each phase's attacks may be resolved in any order desired by the attacking player.

10.3 Attack Limits

No US unit may attack more than once in each of its own sub-command's combat phases, and no Japanese unit may be attacked more than once per US Combat Phase. Except as given rule 10.4 below, those same strictures hold true for Japanese attacking units.

10.4 Japanese Attack Momentum

Whenever a Japanese unit or stack advances-after-combat (see 10.10) in a daylight attack, that advancing force may immediately attack (alone) a second time. If victorious Japanese units advance into the same hexes from different hexes, that newly formed stack may then attack as one. There are never any third combats. No air or BB support may be used in second combats, and they may never be made at night (banzai OK).

10.5 Multi-Unit & Multi-Hex Combat

All units in a single hex attack and defend as a single force; the strength of all the units in one hex is always totaled for combat. A single attack may involve any number of attacking units from several hexes; however, no single attack may have as its objective more than one hex. If more than one attacking unit is in a given hex, all those units must be used as an integral combat strength; they may not be used in different combats, nor may any of them simply sit out the attack.

10.6 Defender Commitment & Integrity

The defending player may not withhold from combat a unit or stack in a hex under attack. The attacker must attack together all the units in a defending stack. Different units in the same hex may not be attacked separately.

10.7 Combat Strength Unity

A given unit's or stack's combat strength is always unitary. It may not be divided among different combats either on attack or defense.

10.8 Terrain Effects on Combat

Defending units in certain types of terrain have their combat strength enhanced or diminished. See the "Combat Effect" column of the TEC printed on the mapsheet. For example, a unit being attacked in a rough hex would have its combat odds shifted one column left (in the defender's favor) due to that fact.

10.9 Combat Results

Combat Results are given on the CRT in the form of strength steps that must be lost by each side. The attacker's losses are to the left of the slash; the defenders are to the right. For example, at 2:1 odds, the combat result on a roll of six is "2/1." That means the attacker would lose two steps and the defender would lose one step.

Note that all USMC and all Japanese ground units other than Beachhead markers start play as two-step units, while all US Army ground units are one-step units to begin with.

When a two-step unit takes a step loss, flip it over so its one-step side thereafter shows upward. One-step units suffering a step loss are simply removed from the map. A two-step unit, once reduced in combat, may never regain that lost step, and a one-step unit, once removed from the map, may never be returned to it.

Both players are generally free to apportion their step losses in each battle as they see fit. The exceptions are that Japanese Beachhead markers and US fort garrison units must always be the last step given up to satisfy combat losses from their hexes. Those two types of units never attack, though other attack-eligible units may attack normally from their hexes. Since they can't attack, they may never be given up to satisfy losses for attacks launched from their hexes.

10.10 Advance After Combat

Whenever a defended hex is vacated as a result of combat, at least one involved victorious attacking unit must be advanced into that vacated hex. More than one involved attacking unit may advance, at the advancing player's discretion, as long as stacking strictures are observed in the seized hex. Exactly which involved unit(s) conduct(s) the advance-after-combat is up to the owning player. Advances after combat must be performed immediately as they occur, before any other combats are resolved.

Old Hands Note. There is no retreat-after-combat.

10.11 Odds Limits & Odds Reductions

Attacks made at final odds greater than 4:1 are resolved as if they were 4:1 attacks. Attacks made at final odds less than 1:3 are resolved as if they were 1:3 attacks.

10.12 Concentric Attack

If a US unit or stack is defending against Japanese attackers coming in from opposite hexes, or against attacking units coming in from three hexes with one hex between each and the next, or against attacking units coming in from more than three hexes, that attack gains a one column rightward (1R) odds shift. This bonus is never available for US attacks. Japanese attackers can't use it when attacking into Ford Island or city or military installation or fortification hexes. (Ford Island is an airfield, and the TEC doesn't prohibit the concentric bonus against such hexes, but the "island" trumps the "airfield" here.)

10.13 Issei Rebellion

Each time the Japanese player attacks into a city hex, he rolls a preliminary die. If that result is a six, rebellion has broken out among the island's Issei. The effect of the Issei rebellion is as follows: in that instigating attack the US defenders get no defensive terrain benefits; plus, afterward, for the rest of the game, all city hexes cost US units two MP to enter (normal defensive terrain benefits return).

10.14 US Fortifications & Fort Garrisons

US fortifications captured by the Japanese give their defensive combat benefits to Japanese defenders in those hexes. US units attacking from a fortification that contains a fort garrison unit have their attack factors doubled for doing so (and that's true even if they combine in an attack with other US units from outside the fort; though, of course, only the units actually attacking from within the fortification would be doubled). Also see rule 6.6.

11.0 Ford Island & Battleship Row

11.1

At the start of each game, the only unit in the Ford Island hex (3020) is the static US Battleship Row counter. That unit remains there until such time as it's eliminated by a Japanese ground or aerial attack (see 11.4 below). While the BB Row counter is in play, no other US or Japanese ground unit may enter the Ford Island hex.

11.2 Ford Island Combat & Movement

Ford Island may be attacked through any, some, or all of its six hexsides; however, all units attacking through those hexsides are halved for doing so (round down all remainders). Normal advance-after-combat rules apply to any attacks onto the island. (That's also true if units other than the BB Row counter are attacking from the island.) Once the BB Row counter has been eliminated, it's possible for US or Japanese ground units to move onto Ford Island from any of the six adjacent hexes. To do so, the moving unit or stack must start its move already in an immediately adjacent hex. The move onto the island uses up all the moving force's movement allowance for that phase. The same is true when moving off the island. US movement onto and off the island may not be blocked by Japanese aerial interdiction missions.

11.3 BB Row Attacking

When the US player pulls his "BB Row Fight" chit (see 5.6), he may make an attack with that counter. To do so, he selects any hex containing one ore more Japanese ground units that's one or two hexes away from it. If the selected hex is immediately adjacent ("one hex away") the US player determines the attack factor of the BB Row counter for that one attack by rolling two dice (or one die twice — expressed as "2d6"), which will result in a temporary attack factor of two through 12. When the target hex is two-away, roll just one die (1d6) to determine the attack factor for that battle. The BB Row counter may never make advances-after-combat, but it also never suffers any step loss when attacking. It never attacks at night or in conjunction with units from other US sub-commands. When attacking at two hex range, it may ignore all intervening terrain and units, friendly and enemy.

11.4 BB Row Defending

The BB Row counter defends normally against Japanese ground attacks (but see 11.2 above). Whenever it defends, it rolls up its combat factor using 2d6, and the BB don't make that roll until after the Japanese player has declared his ground combat air support. No more than one column shift for Japanese aircraft participation may ever be used against the BB counter, and the US player rolls for defensive combat air support normally when it's attacked. The fact the BB may have attacked earlier in a game turn in no way inhibits it from making a defense that same turn. The Japanese player may decide, during any of his combat phases, to attack the BB Row counter solely with his available aircraft. In such cases, each aircraft unit committed is considered to have an attack factor (not a hit number) of one, while the BB roll up their defense factor normally (2d6). Further, in such pure-aerial attacks, IJN aircraft must suffer normal combat losses as if they were ground units.

12.0 Banzai & Night Turns

12.1 Banzai!

The Japanese player may declare "Banzai!" for any of his ground attacks or defenses, day and night. It's the last support declaration made for any battle in which the tactic will be used (after the Japanese BB combat support declaration, the Japanese air support declaration, rolling for US combat air support, and resolving night combat shifts, if any). The effect on Japanese combat losses when making a banzai is to double their normal step losses for that engagement (zero results convert to ones). To determine a banzai's effect on a battle's combat odds, the Japanese player makes a die roll and divides that result by two, rounding down any remainder. That's the combat odds shift in his favor (0-3). All Japanese units in a battle banzai together or not at all; there are no partial-force banzai. At night (see below) banzai is declared after the night attack odds shift has been determined. Also note the involved Japanese units still have their losses doubled even if they ended up with zero column shifts for their efforts.

12.2

Every "Morning," "Afternoon" and "Evening" turn is considered a "daylight" turn. There are only two "Night" turns in the game: turns four and eight. These rules apply only during those two game turns.

12.3

During night turns there are no US attacks except for a possible submarine attack (see 7.11). There is no Japanese Landing Phase during night turns; neither are any aircraft missions flown by either side. At the start of both night turns, take all US "Attack" chits out of their container prior to that player drawing the first one. All units defend normally at night.

12.4

The Japanese player may attack during night turns. As the second-last step (see 11.1 above) prior to finally resolving each one of his attacks during night turns, however, he must roll on the Night Attacks Shift Table printed on the mapsheet. That roll will tell him if there are to be any shifts applied to his attack's combat odds due to it being launched in the dark. Note the shifts may be in or against his favor. If the table result calls for shifts, the Japanese player should again roll the die and divide that result by two, rounding down. That number (0-3) is the number of column shifts applied, for or against the Japanese, due to it being a night attack. During night turns, banzai is declared and resolved after the resolution of the night attack shift situation.

End of rules as printed in the source. The source text ends at section 12.4.