Sudoku and kakuro were so popular that they inspired Nikoli’s readers to come up with their own grid-based number and logic puzzles. He did the same with another American puzzle, “cross sums”, which he renamed kakuro. Nikoli’s editor spotted the puzzle, gave it a Japanese name and refined it so that the given numbers in the grid appeared in a symmetrical pattern. It first appeared in a US puzzle magazine in the late 1970s, and was called “number place”. So it is curious to find out that sudoku did not originate in Japan. For the previous 20 years, however, it had been a staple of the Japanese puzzle magazine Nikoli, and few people outside Japan had heard of it. The boom in interest in Japanese puzzles dates to 2004, when sudoku first arrived in the UK and became an instant international craze. Yet the real reason Japan has become a puzzle superpower is as much circumstantial as it is about cultural traits, and a result of the intriguing history of sudoku itself. Grid logic puzzles also reflect other qualities valued in Japanese culture, such as minimalism, refinement and craftsmanship, and are in tune with a people comfortable with following clearly defined rules. “Puzzles in small grids have the same feeling as hakoniwa.” “The Japanese like to miniaturise,” he says. The puzzles remind him of the tradition of hakoniwa, miniature landscape gardens in a small box that many people have in their homes. Jimmy Goto, chief director of the Japan Sudoku Association, says that grid logic puzzles are a natural fit for the Japanese. Once you have started one puzzle – and there is usually a simple move to hook you in – you are totally in their grip. The step-by-step path to the solution is utterly addictive, since each completed step gives you a buzz and pushes you to the next one.

Puzzles pioneered by the Japanese are always based on grids, have very simple rules, and the solving process involves filling in the gaps through a process of logical deduction.

Types of logic grid puzzles