Added Botsu Bako problem Apr 21, 2017
Momotereu's Heyawake problem is open to members. Try it out on the Botsu Bako (Extra Special Problems) page in the members area.
Maintenance finished Apr 21, 2017
About 10 minutes after 05:00 Apr 21, 2017(UTC).
Due to scheduled maintenance, you could not access to the nikoli.com. Sorry for the inconvenience.
Result of the 264th nikoli.com Puzzle Championship Apr 16, 2017
Congratulations! needTshirt won the 264th puzzle championship! The winner's name is now displayed and will remain on the Champion page of nikoli.com Hall of Fame.
The next puzzle championship will be held from Sun. Apr 30, 2017 13:00 (UTC). The time trial problem will be a Yajilin puzzle contributed by aiko.
Added Slitherlink, Yajilin and Norinori puzzles to The pick of the puzzles page Apr 3, 2017
Most popular Slitherlink, Yajilin and Norinori puzzles are available to members. Play them in the members area, in The pick of the puzzles page.
2017's April Fools' page Apr 3, 2017
2017's April Fools' page can be seen here. Puzzle solving AI under development --- The TOKOLI AI system.