Did you lose to a cheater? Chess cheater check
Type your Chess.com or Lichess username. See which opponents were later banned for cheating, and how many of your losses came down to the board instead.
How it works
The check loads your last 500 games from Chess.com or Lichess, then looks up each opponent's account. Chess.com marks accounts it closed for cheating as closed for fair play violations. Lichess marks accounts that broke its rules, and doesn't say why a closed account closed, so only marked accounts are named.
Everything happens in your browser. KingChess never sees the list.
Questions
How do I know if I played a cheater on Chess.com?
Chess.com closes accounts it catches cheating and marks them closed for fair play violations. The check reads your last 500 games, looks up every opponent and lists the ones closed that way, with links to your games against them.
Can I check my Lichess opponents too?
Yes. Lichess marks accounts that broke its terms of service, which covers engine use but also boosting and sandbagging, so the check says marked for breaking Lichess's rules. Lichess doesn't say why a closed account closed, so those are counted but never listed.
What does "came down to the board" mean?
Those are your losses to players who were never caught: the moves decided them. Coach Bjorn reviews your latest game free and shows the blunders in it.
How long does it take?
Usually under a minute. Loading 500 games takes most of it, and Chess.com opponents are looked up one at a time. A second check within a day is much faster, because the answers are kept in your browser.
Why only the last 500 games?
That covers months of play for most players and keeps the check to about a minute. Going further back means thousands of lookups, one at a time.
Is anything saved or shared?
No. The check runs in your browser, straight from Chess.com and Lichess. Nothing is sent to KingChess, and nobody else sees your results.
Coach Bjorn
Cheaters or not, I'll review your latest game free and point out the blunders. Type your username and pick your site.