Sudoku, today’s most well-known grid-solving puzzle, was originally invented by Howard Garns in 1978. NIKOLI Co., Ltd., a magazine publisher, introduced the puzzle in Japan during the 1980s. Almost 30 years later, its popularity suddenly exploded. Bookstores now carry dozens of Sudoku books. Eventually, other puzzle types will explode in popularity. This new column presents … Continue reading Ripple Effect