Ayu
Ayu Rulebook
Table of Contents
Table of Contents
Definitions
In these rules, "adjacent" always means "orthogonally adjacent". A unit is a singleton or group. A singleton is a piece with no adjacencies to like-colored pieces. A group is a set of like-colored, adjacent pieces.
Play
Black plays first, then turns alternate. On each turn, players must do one of the following actions:
- Move a friendly singleton to an adjacent empty point.
- Take a piece from a friendly group and place it on a different empty point adjacent to the same group. All pieces which were joined in a single group before the move must remain joined after the move.
Every move must reduce the distance between the moved unit and the closest friendly unit. The distance between two units is the shortest path of adjacent empty points between them, i.e. the number of consecutive moves one would need to join them.
If a player can't make a move on his turn, he wins. This usually occurs when said player has joined all his pieces in a single group. If a board position is repeated with the same player to move, the game will be declared a draw. This is known to be a theoretical possibility if both players cooperate to it, which doesn't happen in actual play.
Pie Rule
Players may agree to use the pie rule in order to balance the game. If that is the case, White will have the option, after Black's first move only, to change sides instead of making a regular move.
Examples
Normally, an Ayu board will be much larger than the tiny ones shown in the examples.
The distance rule
The example shows the relative distances between every pair of White units. Four moves are needed to join A and B, while C and A are only two moves away from each other. Therefore, if A is moved, it must get closer to C. Note that the center piece in a group can't be moved if the group would be left split after the move.
Immobilization
In the example, if White plays the marked move, he will lose immediately, as Black will have no moves available on his next turn. Note that this is a legal move, even if the White group is momentarily split during the move. White can win, instead, by entering the sequence starting from the second picture. In this case, White will be immobilized first.
Author's Notes
An essential part of the strategy lies in building long walls between enemy units, thus forcing the opponent to spend many more turns connecting them. Also, playing from the outside inwards is more efficient, as it helps you not to leave any units behind. The distance rule has some interesting tactical effects: sometimes, in order to move a unit (A) in the desired direction, you'll have to first move away the unit (B) which is closest to it so that A isn't "engaged" to B anymore.
Ayu (short for "Attach Your Units") is arguably the quintessential game of approach moves. The rules have been kept to a minimum so as to let the featured mechanism unfold by itself.