The 3rd annual US National Championship of Sudoku occurs in Philadelphia, a precursor to the World Championships also happening this year in the same city. Puzzle master Will Shortz, the editor of the esteemed New York Times crossword and puzzles, is the host of the event at the Pennsylvania Convention Center on October 24.
The object of this number-placement puzzle is to fill a 9 x 9 grid so each column, row, and each of the nine 3 x 3 boxes contain each of the numbers 1 to 9 only once. The puzzle setter provides a partially completed grid.
It is believed that originally a version appeared around the 1890s in France, though the modern Sudoku design is attributed to Howard Garns, a retired US architect who published the first one in 1979 in Dell Magazine. It was then popularized in the Japanese publication Monthly Nikolist in the mid-1980s. Sudoku means single number.
Sudoku has risen rapidly in Britain and Europe, becoming an international hit by 2005. In the US it also became a sensation quickly.
The puzzles for the Philadelphia event were created by Stefan Heine of Germany where he produces puzzles for the German Sudoku Championships and has publishes a number of Sudoku books.
This weekend, hundreds of contestants will gather for the game, narrowing down the best players to face off on stage. After a few rounds, and divided by age categories, the finalists are timed during play to determine their speed. Contestants will be divided by beginner, intermediate, and advanced levels, with a $10,000 prize.
Last year, Wei-Hwa Huang, 33, a former Google software engineer, left his job when he won the top prize at last year's US Sudoku National Championships, beating reigning champ Thomas Snyder, by 26 seconds to complete the puzzle in seven minutes and 39 seconds.
The first championship contest occurred in Lucca, Italy in 2006, followed by Prague, Czech Republic, then Goa, India in 2008, and last year the 4th World Sudoku Championship was held in Zilina, Slovakia, where Snyder lost to Jan Mrozowski of Poland after a 36-competitor playoff.
The 5th World Sudoku Championship organized by the World Puzzle Federation will happen in Philadelphia in April 2010 with the winner of the National Championships attending.