blunder.clinic

Most chess puzzles announce that there is a tactic to find. blunder.clinic tries to feel more like a real game, where you do not know whether a position hides a trick. Its positions come from the Lichess game database, picked where players went wrong according to Stockfish, and each is graded with the Maia engine by how likely a player of your strength is to find the best move.

Every day brings six puzzles for your rating band, with bands around 1200, 1500 and 1800: two easy ones that players of your level solve most of the time, two medium ones around a 50 to 70 percent chance, and two hard ones that fewer than half get right. Hard mode shuffles the order and hides the difficulty, so you cannot tell which is the tricky one. An allow retries box, on by default, lets you try a position again after a wrong move.

After each attempt you see your move next to the move played in the original over-the-board game, and a move analysis panel animates the best continuation. You can sign in with Lichess and add your true rating to help the site pick positions at the right level.

It suits club players who want short, honest practice at not throwing away games, and anyone who finds standard tactics puzzles too easy to spot as puzzles.