He was born on _ _ _ _.

If you're already familiar with Sudoku puzzles, the extra rules for Whodoku puzzles are simple:

• Use the letters at the top instead of the numbers 1 through 9. These letters are provided in the form of a phrase to help you remember them while you're solving the puzzle.
• The circled cells complete the clue for the final answer. Fill these in at the top of the page.
• The shaded cells provide the final answer. Enter these letters on the lines below the corresponding column. When a column has more than one shaded cell, you'll have to determine which letter goes on which row of the final answer.

If you're not already familiar with Sudoku puzzles ...

Each puzzle consists of a 9 by 9 grid of cells which is divided into nine smaller 3 by 3 sections, called boxes. These cells are filled in with the 9 unique letters given at the top of the puzzle. When you're done with the puzzle, each of the rows, columns, and boxes will contain each of the 9 letters exactly once.

Some of the cells already contain letters, called givens. Your task is to figure out the letters that belong in each of the remaining cells. You never have to guess -- you can figure it out with logic and each puzzle has a unique solution. Start with process of elimination. If a cell is in a row with certain other letters, then that cell cannot possibly contain those letters. The same goes for the column and box the cell is in. Through this process of elimination, you can figure out some of the cells, then use those cells to figure out additional cells. Harder puzzles require more advanced logic and you can find many web sites on the internet devoted to Sudoku logic.

Each Whodoku puzzle has a final answer who is a well-known person. As you're solving the puzzle, the circled cells will complete the clue at the top of the page, while the shaded cells will complete the person's name at the bottom of the page. You can wait until you're done with the puzzle to look at the circled and shaded letters or you can fill them in as you're going. Or, if you're stuck on Sudoku logic and need some help, you can guess at the clue words or the name as a way to fill in extra cells.

The Whodoku book contains 100 puzzles, in a range of difficulty levels. For more information, read my blog post explaining why I created Whodoku.

Who-doku: Sudoku with Personality, Sterling Press, June 2008
ISBN-10: 1-4027-4948-1
ISBN-13: 978-1-4027-4948-3