Henry Ernest Dudeney/Modern Puzzles/202 - Noughts and Crosses

Modern Puzzles by Henry Ernest Dudeney: $202$

Noughts and Crosses

Every child knows how to play this ancient game.

You make a square of nine cells, and each of the two players, playing alternately, puts his mark

(a nought or a cross, as the case may be) in a cell with the object of getting three in a line.

Whichever player gets three in a line wins.

In this game, cross has won:

$\qquad \begin {array} {|c|c|c|} \hline \text X & \text O & \text O \\ \hline \text X & \text X & \text O \\ \hline \text O & & \text X \\ \hline \end{array}$

I have said in my book, The Canterbury Puzzles,

that between two players who thoroughly understand the play every game should be drawn,

for neither party could ever win except through the blundering of his opponent.

Can you prove this?

Can you be sure of not losing a game against an expert opponent?

Linguistic Note

The game of noughts and crosses is known in America as tic tac toe.

Sources

• 1926: Henry Ernest Dudeney: Modern Puzzles ... (previous) ... (next): Puzzle Games: $202$. -- Noughts and Crosses
• 1968: Henry Ernest Dudeney: 536 Puzzles & Curious Problems ... (previous) ... (next): Game Puzzles: $471$. Tic Tac Toe