Only released UTC dates appear here. Open any available day and difficulty to replay its original puzzle. A future date or a day before the first release has no public puzzle or solution.
Open the daily Sudoku archive by date
The calendar lists only released UTC dates. Pick a date, then its difficulty; the URL retains both so a language switch keeps the same original. One old day contains three fixed IDs, rather than an arbitrary puzzle selected when you open the page.
Keep an old puzzle’s context
Completing an older board belongs to its original UTC puzzle date. Looking at a replay does not create a completion, and replays do not overwrite the saved game. The calendar cannot recover records cleared from this browser or merge another device’s history. Use the puzzle ID when checking a printed answer against an online original. Each date link opens a full game rather than a completed answer. The solution link is a separate, spoiler-bearing replay of the original givens. If you only want a small clue, return to the active game and open Hint instead. A missing date cannot be created by changing the URL. The service checks the current server UTC date and the configured first release, so prepared future stock stays unavailable. You can print an older original and its matching answer separately, keeping the stable ID with both. Local storage keeps device records; this calendar is a list of public puzzles, not an account backup.
Daily puzzles change at 00:00 UTC. The date shown in the game is the UTC puzzle date. A new day does not replace the puzzle you are currently solving. Completion and consecutive-day records are stored on this device.