Callanish
Callanish Rulebook
Table of Contents
Table of Contents
Material
- A 9×9 square board, with a concentric 7×7 playfield of a different colour.
- 64 white stones.
- 64 black stones.
- 16 grey stones for one of the variants.
Game Rules
These rules are for the 9×9 board. Differences for the 7×7 board are explained in the Variants.
Setup
The board is initially empty. Each player chooses a colour: White or Black. White starts by placing a stone on a vacant square. Black does the same.
Play
Players continue taking turns; however, your turn goes as follows:
- Remove one of your exposed stones from the board (i.e. it cannot be under an enemy stone).
- Add one of your stones to the board.
- Add another one of your stones to the board.
The following rules constrain where you can add each stone:
- It must be a "knight's move" away from the stone you removed. That is to say, either 2 spaces vertically and 1 horizontally, or 2 spaces horizontally, and 1 vertically away from the stone you removed.
- The space on which you place it must have none of your stones, and either:
- be vacant, or
- have an enemy stone, in which case you will place yours on top, creating a stack that you control.
Example: It's White's turn, and she starts by removing her stone from b2 (see left diagram). The knight's moves from b2 are a4, c4, d3, and d1; however, only two of those would be legal plays: d1 is vacant, and a4 has an enemy stone. Both c4 and d3 have white stones, so White cannot add stones to either space. The result of White's turn is depicted in the right diagram. Note that Black cannot remove his stone from a4 until White removes hers, exposing his.
Diagram key: White stack; Black stack.
Game End
If, at the end of your opponent's turn, you have at least 5 of your stones and/or stacks in the same rank, or in the same file, you win.
Compare top and bottom diagrams. In both games, Black has managed to create a Check with five stones along Rank 2, and it is now White's turn. In the top diagram, White can prevent the win by removing her stone from c3, and adding a stone on the black stone at e2 (and of course adding another stone elsewhere). In the bottom diagram, White is unable to thwart Black's victory.
Note: It is entirely possible to give your opponent the win by carelessly removing your exposed stone from a stack.
Black's turn. If he removes his exposed stone from g2, White will win at the end of Black's turn.
A player also loses the game in the unlikely event that he/she is not able to make a legal move.
Notice that ties are not possible.
Variants
Different Board Sizes
Although you can play Callanish on a square board of any odd size, smaller boards tend to provide sharper, more exciting games; however, boards smaller than 7×7 don't make for much of a game. Thus, we have provided you with the two best board sizes: 9×9 and 7×7.
7×7 Board
To win the game, you must have at least 4 of your stones and/or stacks in the same rank, or in the same file.
Extrapolating
For an n x n board, the number of stones/stacks you must have in the same rank or in the same file in order to win is n/2, rounded up. For example, to win on an 11×11 board, you need 6 to win. Remember, use only odd values for n; even values are not recommended.
Non-Square Boards
An interesting variant involves boards that are not square and/or have "holes". These boards can be easily designed by adding grey stones on empty squares to reduce the playable area. In such boards, the victory condition is not uniform throughout the board but changes depending on the rows and files concerned. For example:
You win for having any of the following at the end of your opponent's turn: 3 stones along the outermost files and ranks (a, i, 1, or 9); 4 stones along files b or h, or ranks 2 or 8; and 5 stones along the central files and ranks (c – g and 3 – 7).
In general, it is a good idea to avoid files and ranks with an even number of squares.