NoGo is short for No Capture Go. It has also been called Anti Atari Go according to an online article on Sensei's Library. While the rules are similar to that for the ancient Asian game of Go, the strategy and tactics are completely different.
NoGo can be played on any graph. However, we assume a square nxn grid, called the board. Plays are made on the intersections of the grid, which are called points. Play starts with an empty board. Players are called Black and White. Black moves first. A move consists of putting one stone of the player's color onto an empty point of the board. Players are not allowed to pass.
Connected components of stones of the same color are called blocks. Adjacent empty points are called liberties of a block. In NoGo, all blocks must have at least one liberty. Therefore, the following two types of moves are forbidden in NoGo:
A NoGo game ends when the player whose turn it is to play has no legal move. This player loses the game.
In other words, the player who makes the last move wins the game.
In the figure below, Black has just played the marked move on A1 and won the game. White has no legal moves. There are only two empty points left. However, A3 would be suicide, and C2 is also illegal because it would capture C3, as well as A1, B1 and B2.
In the next figure, White to play can choose between A and B. All other moves are eiter capture or suicide. After either of White's moves, Black has three choices. Can you find them?
Martin Müller