The Washington Post Sunday
How to Play
The rules of Samurai Sudoku are the same as in the popular Sudoku puzzles that appear in the daily comics section.
As with standard Sudoku, the Samurai version requires no math, just logic, reasoning ... and an iron will. The goal is to fill in each column, row and 3X3 box with the digits 1 through 9 without repeating any. The twist in Samurai Sudoku is that the digits that appear in the overlapping boxes must work for both puzzles.
A piece of advice to get you started: Don’t focus completely on one grid at a time. Keep the whole puzzle in mind as you go, because filling in a number in one grid could give you clues to another. What’s important to understand is this: Each Samurai puzzle is ONE puzzle, not five separate Sudoku puzzles that just overlap each other. Occasionally people claim that, for example, the "bottom right" 9X9 puzzle had more than one solution. Well, yes it may, but the entire puzzle can be solved in only one way. Never resort to guessing! For more tips, go to http://www.djape.net/sudoku/wp/?p=144.