The Times Samurai Su Doku 11: 100 Extreme Puzzles for the Fearless Su Doku Warrior

The Times Mind Games, Richard Rogan

For anyone who loves the challenge of Su Doku but manages to solve them within minutes, you can now enjoy the extended mental workout and ultimate endurance test of a five grid interlinked system. This is Su Doku multiplied: every column, row and 3x3 box must contain the digits 1 to 9. Where the puzzles...