Square board connection game with very simple rules. Colder than Konobi.

DEFINITIONS

Two like-colored stones are strongly connected if they are orthogonally adjacent to each other, and weakly connected if they are diagonally adjacent to each other without sharing any strongly connected neighbor. Note that two stones of different colors are never considered to be connected.

A chain is a set of (weakly or strongly) connected stones.

PLAY

Starting with Black, the players take turns placing stones of their own color on empty points of the board, one stone per turn.

It's illegal to place a stone on a point where it makes a weak connection unless placing an enemy stone on that point would also make a weak connection. It's also illegal to form a crosscut, i.e. a 2x2 pattern of stones consisting of two weakly connected Black stones and two weakly connected White stones.

If a player can't make a move on his turn, he must pass. Passing is otherwise not allowed. There will always be a move available to at least one of the players.

The game is won by the player who completes a chain of his color touching the two opposite board edges of his color. Draws are not possible.

PIE RULE

The pie rule is used in order to make the game fair. This means that White has the option, after Black's first move only, to remove Black's stone from the board and place a White stone on a point diagonally symmetrical to it.