Ultimate Tic-Tac-Toe
Two players play tic-tac-toe on nine boards at once. The cell you choose does two things: it places your mark, and it tells your opponent which board they must play on next. Own three of the small boards in a row to win.
The worked example
The nine boards sit in a 3×3, in the same arrangement as the cells inside each one. Suppose you play the top-right cell of the top-left board. That mark sends your opponent to the top-right board, because that cell occupies the top-right place of its own board. The same rule applies everywhere: the center cell of any board sends the next player to the center board, and playing the center of the center board sends them right back there.
Players and turns
X is player 1 and moves first. O is player 2. Players alternate, one mark per turn. You cannot pass.
On the first move, X may play in any empty cell. Every board is open.
Where you may play
After a mark, the next player must play in the small board named by that cell's place.
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If that board is still open, it is the only board they may play in. A gold frame marks it.
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If that board has already been won, or is full and drawn, they may play in any board that is still open. Every open board is framed. This is a free move.
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A board you just won does not stay open, even when it still has empty cells. Winning a board and sending the next player back to that same board is a free move.
Small boards
A small board is an ordinary 3×3 tic-tac-toe.
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Three of your marks in a row, column, or diagonal claims the board for you, immediately, including when that mark also fills the last empty cell.
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A claimed board is closed. Nobody plays there again.
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A full board with no line of three is drawn. It belongs to nobody, and it blocks every large-board line that would pass through it.
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The large mark on a claimed board is a reminder of who owns it. The nine small marks stay visible underneath. A drawn board is washed in slate and shows no owner.
Winning the match
After every mark, the game checks in this order:
1.
If the player who just moved owns three small boards in a row, column, or diagonal, they win at once. Empty cells and open boards do not matter, and winning on the move that closes the last open board is still a win.
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Otherwise, if the next player has no legal mark, the match is a draw.
3.
Otherwise play continues.
Play does not end just because no large-board line is still possible. As long as someone has a legal mark, the match goes on. Drawn boards simply make the lines through them impossible for both players.
The board on a phone
The nine boards stay visible as a small overview. The board you can play in is drawn large enough to tap. When you are sent to one board, only that board is enlarged. On a free move, every open board is enlarged and stacked, and the page scrolls.
The log
Each mark is recorded as where it was played, for example "X played center of top-right board". Claiming a board, drawing a board, and winning the match are recorded on their own lines after the mark.