Sixy Sudoku Wacky ●

Book excerpt: Peter Ritmeester is the inventor of the Hyper Sudoku, where four gray regions also contain 1-9. By applying this idea to a 6x6 sudoku, an entirely new dimension of logic is created, making a Sixy perhaps even more fun than a 9x9 sudoku. Not plain hard work, but plenty of logic and insight. Errors are unlikely, with twice as many puzzles (and a six page How-To) in the same amount of space! In a Wacky Sixy few of the regions enclosed by a boldface border are 2x3. This makes things much more difficult. Ritmeester, owner of PZZL.com, created the puzzles for all sudoku books presented by Will Shortz, with average reviews of 4.5 stars.