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asmFish: Updated Avril, 8 2019


Available for: Windows, Linux, Android 64bit, macOS.


Updated to: Rank threats on pinned pawns bench 4503866.


asmFish is a Stockfish derived engine written in assembler, the strong point of it is to have a smaller executable, hence faster.

Originally conceived by Mohammed Li, it was maintained then by Lyudmil Antonov and later by Counterply (

The rewriting means that asmFish could not be the latest beta Stockfish translation and that there could be bugs, due to the minor testing time of this engine compared to the Stockfish releases. Anyway in one year of testing I've seen it works very well on powerful mainframes with many threads/cores.

Unluckily the official asmFish release is not updated so frequently lately.

This software lies under the GPL license, asmFish official GitHub page:

The BookDepth issue:

WARNING: I've accidentally found a serious issue that could totally spoil many test you've made with BIN books: the BookDepth value is different between asmFish and the other engines. asmFish measures the BookDepth in plies, that is 1/2 move (1 White move + 1 Black move = 2 plies), while the other engines measure it in effective moves. So if you are making a test between asmFish and the other engines with a limited amount of book moves, please be sure to set double the value for asmFish.

For example, we want to make a test up to the move 15: for asmFish BookDepth will be 30, while for other engines like Stockfish Polyglot or Brainfish will be 15.







21/01/19 poll average perc.: 8.5.


Maximize its strength by using my opening book Goi.



asmFishW_2019-04-05_base.exe single processor benchmark:





- Windows

- asmFishW_2019-04-05_base.exe
- asmFishW_2019-04-05_bmi1.exe
- asmFishW_2019-04-05_bmi2.exe
- asmFishW_2019-04-05_popcnt.exe

- Linux:

- asmFishL_2019-04-05_base
- asmFishL_2019-04-05_bmi1
- asmFishL_2019-04-05_bmi2
- asmFishL_2019-04-05_popcnt

- Android 64bit only:

- armFishL_2018-07-23_v8

- macOS:

- asmFishX_2019-04-05_base
- asmFishX_2019-04-05_bmi1
- asmFishX_2019-04-05_bmi2
- asmFishX_2019-04-05_popcnt

Matefinder is also included in the package.