Global Interest in Logic Puzzles

The craze for sudoku in Britain has been spreading to the United States. More than two million sudoku-related books have been sold in Britain alone since the logic puzzle's introduction by the Times newspaper one year ago. In fact, the puzzle's name, sudoku, has been declared "word of the year" by the Language Report. In the U.S., sudoku made its appearance in the New York Post in April, 2005. Although the original version of sudoku, known as Number Place, was initially published in America in 1979, the Japanese version has made its daily appearance in newspapers nationwide. According to the New York Times, more than half the country's leading newspapers provide one or more sudoku puzzles a day. At the heel of sudoku's success, nonogram - a logic puzzle that reveals a hidden picture when solved - is also becoming well-known around the world.

The explosive popularity of logic puzzles expanding in the West has not struck Japan yet. It seems that the Japanese news media hasn't given much attention to the logic puzzles as a developing cultural sensation, even though there has been a growing core of puzzle enthusiasts (among males) and a rising public interest over the years. Perhaps, the media preferential treatment toward the young and woman consumers overlooks a potential cultural boom of the puzzle industry. Nowadays, more than 600,000 copies of sudoku magazines appear monthly on the bookshelves. The picture-forming logic puzzle, known in Japan as Oekaki-Logic invented by Tetsuya Nishio, has been seen as an increasing pastime activity. Since December 2002, Sun Magazine Group, a major Japanese publishing group, has been including picture-forming logic puzzles in all issues of Oekaki Mate magazine.

The origin of logic puzzles can be traced to the Latin Squares, developed by Swiss mathematician Leonhard Euler in the 18th century. A more complex version (nine quadrants of 3 by 3 cells) created by Howard Garns first appeared in the American Dell magazine in 1979, and later introduced by Nokoli Inc. in Japan in 1984. It was not until 1986 when Nokoli presented a modified version with given numbers in a symmetrical pattern that sudoku became a hit among Japanese puzzle fans. Wayne Gould, a retired New Zealand judge who discovered sudoku on a trip to Tokyo in 1997, introduced the mind-bender to the Times newspaper, which set off a British rage. In 2005, sudoku reappeared in the U.S., but this time in a newspaper with a wider circulation of readers.

Japanese logic puzzle has different brand names depending on the developer, the publisher, or the country where it is circulated. For example, Oekaki Logic (in slight variations) is known in Japan - as Edel by Nikoli, Illust-Logic by Gakken, Cosmic Publishing, and Nihon Bungeisha, as Oekaki-Mate by Sun Magazine, as Logic-Jack by Doumsha, or as Picross by Nintendo; and outside of Japan - as Paint By Numbers, Pic-a-Pix, Nonogram, Griddlers, Picture Crossword or Crosspix.

The major appeal of sudoku and other Japanese logic puzzles is attributed to their simple rules and the application of logic without special knowledge of words or math. As a classic puzzle-type, logic puzzles can range from fairly easy to fiendishly difficult. The merits of these brainteasers are cited as follows: satisfaction from solving or completing something difficult; prevention of memory decline; development of logic skills; and pure mental entertainment. 

Although Japanese have developed many types of logic puzzles for the last twenty years, the most common ones found in puzzle magazines are the following: sudoku, kakro, nonogram, slither link, and divide by squares.

• Sudoku - the common version consists of nine quadrants of 3 by 3 cells, which must be filled in so the numbers 1 through 9 appear just once in each column, each row, as well as in each quadrant. Numerous variations of sudoku have been developed (Japan and abroad) with different shapes and sizes: 5x5 grids, 8x8 grids, 16x16 grids, 25x25 grids, grids with multiple overlapping regions, and even a three dimensional cube.
• Kakro (also known as Cross Sums) - basic math calculation by inserting 1 to 9 into each cell such that the sum of the numbers in each entry matches the horizontal and vertical totals given at the ends of rows and columns.
• Oekaki Logic - a hidden picture is revealed when appropriate cells in a grid are colored or left blank according to numbers given as clues at the ends of rows and columns.
• Slither Link (also known as Fences) - various patterns of drawing one loop based on only four digits (0 to 3) as clues.
• Divide by Squares - a grid is divided into rectangular and square pieces such that each piece contains exactly one number that represents its area size.

Logic puzzles will spread globally not only for their numerical formats, but also for their various patterns and forms in using logic to arrive at solutions. As a universal game, logic puzzle crosses all language, cultural and border barriers. As more people become exposed to logic puzzles, the Japanese versions will make a killing in the global market. 

(First published on UniOrb.com, November 2, 2005)