How to play

A board at any level contains nine positions. At the deepest level those positions are playable squares. Every level above them contains nine child boards instead.

Players alternate. X always moves first. Claim three positions in a row inside any board and that board becomes yours.

Every square has a hierarchical address. On a depth-two board, playing in square 2 of board 1 has the address [1, 2]. Your rival must then play inside board 2 — the rest of the address, one level up.

The same rule repeats at any depth: a move at [A, B, C, D] sends your rival into the board at [B, C, D], where they choose the remaining coordinate themselves.

The destination board is always highlighted, so you never have to remember it. You may also browse the whole tree at any time — the board that is actually playable glows.

If the forced destination is already won, drawn or full, the constraint relaxes outward to its nearest playable ancestor. In the worst case it relaxes all the way to the root, where every open square is legal. A player who is still to move always has a move.

Won and drawn boards are locked: their squares can no longer be played.

A board that you have claimed counts as one of your marks inside its parent board. Three claimed boards in a row claim the board above them, and so on up the tree. Claim the root board and the match is yours.

A board is drawn when all nine of its positions are decided with no winner. A board whose children are all decided counts toward its parent's draw, and if the root board itself is drawn the match is a draw.

Hosts can add a per-turn timer. If it runs out, the match goes to the opponent.

Online rooms are server-authoritative: every move is validated against the stored match state, and turns synchronise live for both players. If you drop out, reopen the match link and you will be placed back in your seat.

Playing locally, both players share one screen. Online, share the invitation link or the six-character room code.