American Thomas Snyder won the second World Championship in sudoku in the Czech capital on Saturday, organizers said.
Snyder, who was runner-up in the sudoku's first ever World Championship held in Italy last year, claimed the title ahead of Yuhei Kusui of Japan. Slovakia's Peter Hudak was third, organizer Vitezslav Koudelka said.
Japan won the team competition, followed by the United States and the Czech Republic.
Competitors from 32 countries took part in the championship.
Sudoku, an increasingly popular puzzle, consists of a grid of nine rows of nine boxes, which must be filled in so the numbers one through nine appear just once in each column, row and three-by-three square.
The puzzle, which originated in Japan, has successfully spread around the globe, including Britain and the United States.
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