In Your Hands

Swindle Sudoku

by Werner Miller Werner Miller is a retired teacher of mathematics, whose hobbies are recreational mathematics and magic. A magical inventor and writer, Werner has produced a prolific volume of work, mostly what he calls semi-automatic card tricks based on mathematical principles. He is the author of "Fast von selbst", "Alles Miller oder was", "Ratatouille", more than 300 trick contributions to various magazines and web sites and more than 30 related computer programs. In addition, Werner is also a staff member of the German magazine "Magische Welt", a columnist for the British magazine "The Magician", and regular contributor here at Visions. Werner's first English-language book, Ear-Marked, is available here. Sudoku puzzles are nowadays very popular. If you want to lay the foundations for your reputation as a mental prodigy, prove that you can solve such a puzzle within one minute. Here's how. Start with an empty 9x9 grid. Let your audience call out the numbers 1 through 9 in any order. Write the first number into box A, the next one into box B, the next one into box C and so on. (See Figure 1. Each number is used only once, e.g. A = 3, B = 7, C = 1, D = 9, E = 4, F = 8, G = 2, H = 6, I = 5.) The object is now to fill in every empty box in the grid so that every 3x3 square, every column and every row contains the numbers 1 through 9. First complete the center row by inserting alternately one number from above and one number from below. (Figure 2) Then complete the center column by inserting alternately one number from the left and one number from the right. (Figure 3) Now, in your mind, double the number sequence of the center row to ADGBEHCFIADGBEHCFI and "cut" out fitting 9-number "strips" to complete

every row. (Figure 4) Have fun!

Werner Miller