Kendoku, Volume 2: 100 Puzzles to Build Your BrainPaperback, 17 February 2009

Can't get enough Kendoku? Kendoku: Volume 2 contains 100 new puzzles that range from mild to mind-bending. Following the footsteps of Sudoku, Kakuro and other number logic games, Kendoku is one more addictive logic puzzles. Using logic together with the four math operations (+ - × ÷), these fascinating puzzles offer endless fun and intellectual entertainment to puzzle fans of all skills and ages.

The puzzles, either 6 x 6 or 9 x 9, look like Killer Sudoku games but in addition to numbers, players also contend with math operators (+ - × ÷) within "fences" on the puzzle. Players arrive at the total at the top left of the fenced area by using the operator on all the numbers within the fenced area. Although the solution is a valid Sudoku solution, Kendoku numbers are allowed to be repeated within a fenced area as long as the result doesn't break the rules for a valid Sudoku.