About Chess Problems
A free site for solving chess compositions on an interactive board. The problems come from YACPDB, the open chess problem database; the site checks your moves against the composer's published solution.
What is here
Over 580,000 problems, in five genres that the site keeps completely separate. Each has its own list, filters, progress and history.
- Direct mates#2 to #5 and longer · about 406,000
- Helpmatesh#1 to h#5, including duplex and multi-solution · about 85,000
- Selfmatess#1 to s#5 and longer · about 53,000
- Endgame studiesWhite to win or draw · about 32,000
- Retrosretrograde analysis · about 1,500
A Daily problem (a mate in two) appears on the home page every day, with an archive of past days. A Themes guide explains the classic ideas of problem chess — battery, zugzwang, Grimshaw, Novotny, Plachutta, model and ideal mates — each on a prize-winning example you can solve first. There is also a page for the problems set at the World Chess Solving Championship 2026, laid out like the official solving sheets.
Solving
- You play the solving side; the site plays the defence. In direct mates and selfmates you are White and Black's replies are played for you. In helpmates you play both sides. In studies you are White with no move limit.
- Every move is checked against the composer's solution tree, so tries, refutations and all thematic variations are known to the site. After you finish (or give up), the full solution is shown with every variation, and each move can be clicked to see it on the board.
- Twin problems show every twin's position and solution. Helpmates with several solutions ask you to find them all.
- Hints come from Stockfish running in your browser. An analysis board lets you move pieces freely while thinking, without affecting your answer. Where YACPDB's solution stops early, or in studies, you can play the position out against the engine.
- While you are solving, the composer, source and award are hidden, as at a solving tournament. They are shown once you have finished.
- Filters by stipulation, piece count, year, theme and award; search by composer; bookmarks; a history of everything you have solved.
Rated mode
A matchmaking mode that picks a problem near your current strength. Ratings use the Glicko-2 system, for players and for problems alike, so every problem's difficulty is learnt from how solvers actually do on it. A solve counts as a win only when it is perfect: no wrong move, no hint. There are separate rating pools for direct mates, helpmates and selfmates, and a difficulty selector from very easy to very hard.
Review mode
Spaced repetition for problems you have played in rated mode, scheduled with the FSRS-4.5 algorithm. Problems you got wrong come back sooner; problems you keep solving cleanly come back at ever longer intervals.
Where the problems come from
All problem data — positions, stipulations, solutions, composers, sources and awards — comes from YACPDB (Yet Another Chess Problem Database), maintained by Dmitri Turevski and its contributors. Every problem on this site links back to its YACPDB entry. The site takes orthodox problems only; fairy chess has a sister site.
Solutions in YACPDB are written by hand in a range of notations, and the site parses them into move trees so they can be played on the board. Where a solution cannot be read or played, the problem is kept out of the rated pool, but it remains in the lists.
Who made it
Chess Problems is made and run by Ushiyutvj, a chess problem enthusiast, as a one-person project. The source code can be read on GitHub, where bug reports and suggestions are welcome as issues. News about the site is posted on X.
Privacy
The site collects anonymous usage data — which problems are attempted, which moves are tried, how long solving takes — to improve the problem ratings and the site itself. No account is needed and no personal information is stored. Your progress, bookmarks and ratings live in your own browser. See also the commerce disclosure.