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Welcome to Stockfish!

Stockfish is a free, powerful and open-source UCI chess engine derived from Glaurung 2.1.
Stockfish is not a complete chess program and requires a UCI-compatible graphical user interface (GUI) (e.g. XBoard with PolyGlot, Scid, Cute Chess, eboard, Arena, Sigma Chess, Shredder, Chess Partner or Fritz) in order to be used comfortably.
Read the documentation for your GUI of choice for information about how to use Stockfish with it.

Stockfish features two evaluation functions for chess:

1. The efficiently updatable neural network (NNUE) based evaluation is the default and by far the strongest.
2. The classical evaluation based on handcrafted terms remains available.

The strongest network is integrated in the binary and will be automatically downloaded during the build process.
NNUE evaluation benefits from the vector intrinsics available on most CPUs (sse2, avx2, neon, or similar).