The magic nine

Four games on the magic board

The magic nine — from the book's pages

• Each of the numbered balls is placed in a hollow on the board so that the sum of the numbers in a line — vertical, horizontal or diagonal — comes to fifteen. The riddle is easy to solve with the pattern: write the numbers in diagonal rows in the rhombus-shaped diagram, and they «slide» into place in the square.

The magic seven — from the book's pages

• Only the balls 1 to 7; the holes to the right and left of the centre hole are not used. Arrange the numbers so that the sum of any line comes to 12.

Magic tic-tac-toe — from the book's pages

• Two players share the balls: one gets the even numbers, the other the odd. The one with the odd numbers has one ball more and begins, placing a ball in any of the nine holes; then the opponent. The aim is a line of three numbers that together make fifteen. In the next game the players swap.

Do-guti — from the book's pages

• A blocking game from India on the corner holes and the centre hole. Two balls each, placed in holes joined by a line; one hole stays empty. The players take turns moving along a line to an adjacent empty hole. No captures; whoever blocks the opponent so that he cannot move wins.

My choices

• In do-guti the lines are the two sides and the two diagonals — the hourglass. With all four sides nobody could ever be blocked, so the book's picture is read that way. You have the balls at the top and begin. The same position three times is a draw.
• In tic-tac-toe the line counts whoever the balls belong to, as the book says. The machine looks five moves ahead.
• «Hint» places one ball correctly in the nine and the seven, from a solution that fits what you have already placed.

New game