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Mehdi
MehdiFounder of Chessigma

How Chessigma analysis works

See how Chessigma grades moves (Sigma to Clown) in the free chess game report, why depths reach 50 in theory lines, and why our accuracy is close but not identical to Chess.com.

Chessigma game report showing accuracy, Elo estimate and move labels

Wondering why your Chessigma accuracy isn't a carbon copy of Chess.com's game report? Or why some moves run at depth 14 while others dive to depth 50? Here's the story behind our browser-powered Stockfish, our homemade move labels, and what's coming next.

Stockfish runs in your browser

Chessigma compiles Stockfish 16 to WebAssembly, so your own CPU analyses positions instead of an expensive cloud server. With roughly 7 000 unique visitors a day that keeps our hosting bill sane and lets us promise the core report will stay free forever.

Speed on desktop is solid, but we know mobiles can feel sluggish. A faster build with multi-threading and incremental depth is implemented on desktop, but not yet on mobile.

Why depth 14-50?

For most moves we stop at depth 14 a practical balance between insight and waiting time which is also close to what you would get on Chess.com. When a position matches the Lichess opening book, we reuse a cached evaluation that can reach depth 50. Soon you'll be able to crank the depth as high as your hardware allows via a new "Analyze Deeper" button.

Analysis panel showing depth slider and best lines

Unlimited depth toggle enabled soon

Understanding our move labels

After a friendly trademark chat with Chess.com we coined our own set of labels. Here's the gist:

  • Sigma moveSigma: no need for explanation
  • Awesome moveAwesome: was hard to find
  • Best moveBest: top engine line
  • Nice moveNice: solid
  • Ok moveOk: fine but there is better
  • Theoretical moveTheoretical: book
  • Strange moveStrange: engine raises an eyebrow
  • Bad moveBad: that sucks but there is worse
  • Clown moveClown: please don't do that again

Why scores differ across sites

Stockfish only spits out numbers. Each platform turns those numbers into percentages, Elo estimates, and labels using its own secret sauce. Our algorithms aren't the same as Chess.com's or Lichess's, so expect similar but not identical results — like two coaches grading the same test.

FAQ

Is there any risk of being banned for using Chessigma?
No.
Will the report stay free?
Yes.
Can I analyze bulk PGNs?
Not yet. Single chess game analysis first; bulk uploads are on the roadmap.

Run a game review

Paste a PGN or a Chess.com / Lichess username and see if your last move was Sigma or Clown.

Try it now