On a mid-October Monday, shortly before 9 a.m., 179 elite puzzlers made their way into the ballroom of a Toronto hotel and found their allocated seats for the World Sudoku and Puzzle Championships. Quiet descended as proctors distributed booklets for Round 1: nine Sudoku puzzles, with a 45-minute time limit. He is a three-time world Sudoku champion, and in 2018 he won the title of world puzzle champion, making him the first person to win both honors. The annual championship event comprises two days of Sudoku, followed by three days of other types of pencil-and-paper logic puzzles. There were also trickier variants, such as “Difference Sudoku,” for which the standard rules apply, but also each number shown in a circle between two adjacent cells indicates the difference of the numbers in those two cells.

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Persons: puzzlers, Valentin Miakinen, Hwangrae Lee, Thomas Snyder, “, Snyder, ”, Laura Tarchetti, Toni Borozan, Jouni Sarkijarvi Organizations: San Francisco Bay Area Locations: Toronto, France, Korea, San Francisco Bay, revel, Croatia, Finland