Obsidian

A top tier UCI chess engine written in c++, that I started developing in april 2023.

As of 18 July 2024, Obsidian is the 3rd strongest engine at 10+1s, after Stockfish and Torch. January 2025: It is 3rd in SPCC too.

Building

git clone https://github.com/gab8192/Obsidian
cd Obsidian
make -j nopgo build=ARCH

ARCH choice: native, sse2, ssse3, avx2, avx2-pext, avx512. native is recommended however. You can remove the nopgo flag to enable profile guided optimization.

Neural network

Obsidian evaluates positions with a neural network trained on Lc0 data.

Credits

• To Styxdoto (or Styx), he has an incredible machine with 128 threads and he has donated CPU time
• To Witek902, for letting me in his OpenBench instance, allowing me to use massive hardware for my tests
• To fireandice, for training the neural network of Obsidian 9.0
• The neural network of obsidian is trained with https://github.com/jw1912/bullet