CorChess is a clone of Stockfish [source code] [source without LP] maintained for better performance on long time controls,
trying at least partially to fill the gap between regular tests and demands of correspondence players.

My main idea is to improve the following scalability of Stockfish 8.
Most patches will be tested at 40+0.4 time control (1 thread, 16 MB hash, until clear decision),
while depth dependent formulas and regression tests will use 160+1.6 time control (1 thread, 64 MB hash).

Please contact me ( about your experiences with CorChess,
or in the case that you want to be on the CorChess mailing list.

Although I mainly use 2moves book, I also recommend to use the following opening positions:
Test1 (100 positions for 200 games)
Test2 (500 positions for 1000 games)

Regression tests and tournaments between CorChess and Stockfish
Version Opening book Time control #games Result Elo gain
CorChess 1.3 2moves_v1 160+1.6 10000 / 10000 1236-1182-7582 +1.88
CorChess 1.5 8moves_v3 2500+25 512 / 512 26-22-464 -
Regression tests will be done after several patches. Watch games LIVE.

From Stockfish to CorChess (in detail)

If you want to support the project please send your small donations by PayPal to
The amount of donated money will be displayed here (within 48 hours), and it will be used only for testing CorChess.
You can also send your ideas / codes on how to improve Stockfish on higher depths (above 20).

Money donated so far: $70

Motto: Alone I can nothing, with God I can everything (St. Vincent Pallotti).