Sudoku fever is on! Which book in the Martial Arts Sudoku series will provide the perfect challenge for you? The skill level recommended to solve these puzzles is ranked in the same way as Japanese karate levels—by different colored belts. Will the Purple Belt collection leave you scratching your head?
Frank Longo is a freelance puzzle creator whose books have sold more than two million copies. His sudoku books include Hip Pocket Sudoku.
