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 overlap, the rows and columns do not go beyond their usual 9x9 length but the interlocking boxes give you more clues – and more complexity. With another 100 new Samurai puzzles to vex you for hours, lose yourself in the four levels of this book:10 Easy, 40 Mild, 40 Difficult, 10 Super difficult. Even the speediest of Su Doku solvers will be agonizing over these ultra-complex, extended brainteasers. These are the most difficult Su Doku puzzles in
The Times
range.