The World Sudoku Championship (WSC) is an annual international puzzle competition organised by a member of the World Puzzle Federation. The first event was held in Lucca in 2006. National teams are determined by local affiliates of the World Puzzle Federation. The competition typically consists of 100 or more puzzles solved by all competitors over multiple timed rounds, including classic sudoku, variations and other puzzle types, normally followed by a playoff for the top qualifiers to determine a champion. Examples of rounds include the Relay round, where an answer from one puzzle contributes digits to the start of the next sudoku, and the "World Record" round, in which solvers competed to set a Guinness World Record for fastest sudoku solution.
Of the 15 championships held so far, Kota Morinishi of Japan (2014, 2015, 2017 and 2018) has been the most successful winner with four individual titles, over Thomas Snyder of United States (2007, 2008 and 2011), Jan Mrozowski of Poland (2009, 2010 and 2012) who have each won three.
From 2007 there has also been a team competition. Japan is the most successful team, having won the title in 2007, 2012, 2014, 2015 and 2018; Czech Republic (2008, 2016), Germany (2010 and 2011) and China (2013, 2017) have won this title twice; Slovakia (2009) also won a title.
Starting from 2011, the event has been held alongside the World Puzzle Championship.
