Tic-tac-toeकाटाकुटी

The grid

The classic game is played on a grid of 3 by 3 squares, drawn as two lines across and two lines down, and three in a row wins.

Five in a row is played on a grid of 9 by 9 squares, 81 in all, and you need five in a row to win. You choose the grid before the match starts.

Taking turns

The first player at the table draws crosses and the second draws noughts, and each keeps the same mark for the whole match.

Crosses start the first game. After that the first move changes hands every game, so noughts start the second game, crosses the third, and so on.

On your turn, mark any empty square. You must mark one: there is no passing. A mark stays where it is drawn; it is never moved or rubbed out.

On the big grid the squares are small on a phone, so a tap first shows your mark in pencil. Tap the same square again to ink it, or tap another square to change your mind. With a mouse on a big screen, one click is enough.

Winning a game

• On the 3 by 3 grid, the first player with three marks in a straight line wins: a row across, a column down, or one of the two diagonals.
• On the 9 by 9 grid you need five of your marks in a straight line, in any of the same four directions. A longer line counts too, so six in a row also wins.
• The winning line is struck through. If one mark completes two lines at once, both are struck, and it still counts as one game won.

Drawn games

A game is drawn when every square is marked and nobody has a line.

It is also drawn as soon as no line can be made any more: when every possible line on the grid already holds at least one cross and one nought, the game stops there instead of making you fill the last squares for nothing. On the big grid a drawn game nearly always ends this way, before the grid is full.

A drawn game does not count for either player. The next game starts on a fresh sheet, and the player who did not start the drawn game starts the next one.

The match

A match is first to 3 games won, unless you chose first to 1 or first to 5 before starting.

So that a match between two careful players always finishes, it also stops after three games for every win needed: 3 games for first to 1, 9 for first to 3, 15 for first to 5. Whoever has won more games then takes the match. If both have won the same number, the match is drawn.

Where these rules come from

Katakuti is played by the same rules as tic-tac-toe anywhere: we found no Nepali source that describes a different rule. Where tables do differ, this one does the following:

• Three in a row on a 3 by 3 grid, with the players taking turns, is the standard game (Wikipedia's tic-tac-toe article). The article notes that there is no fixed rule for who goes first, though crosses usually start. Here crosses start the first game and the first move then alternates, so both players move first equally often.
• Five in a row follows freestyle gomoku, in which a line of five or more wins (Wikipedia's gomoku article). Gomoku is traditionally played on a 15 by 15 board; this table uses 9 by 9 so that the squares stay big enough to tap on a phone.
• Moving first is a big advantage in five in a row: on a 15 by 15 board the first player can force a win, while computer searches have shown that the game is a draw with perfect play on 7 by 7 and 8 by 8 boards (Wikipedia's gomoku and m,n,k-game articles). Changing the first move every game keeps a match fair on any board.
• Stopping a game as soon as no line can be made is this table's own rule. On paper, players simply stop when they see it.
• The match of first to 3 with drawn games not counting, and the limit of three games for every win needed, are this table's own rules, so that a match is a real contest and always ends.

Three in a row or five in a row

Three in a row is the classic 3 by 3 grid: quick, and always a draw if both players are careful. Five in a row is played on a 9 by 9 grid; it takes longer and leaves much more room for attacks.

First to 1, 3 or 5

Choose how many games win the match. First to 1 is a single game, played again if it is drawn, three games at most. First to 5 is a longer contest of up to 15 games.