DroidFish

From the README: “DroidFish is a feature-rich graphical chess user interface, combined with the very strong Stockfish chess engine.” It is “primarily designed for engine analysis of chess positions and viewing and editing of chess games”, and can also play. It is made by Peter Österlund, who also wrote the second engine it includes: “A much weaker chess engine called CuckooChess is also included in DroidFish. Its primary feature is that it can be made to play very weakly so that even beginners have a reasonable chance to beat it.”

What it does

• Analysis: the engine evaluates the position as you step through a game, showing its best lines and drawing its suggested moves as arrows.
• Playing: as white or black against the computer, two players on one phone, or computer against computer. Both engines can be set to a lower strength; “At the lowest setting, CuckooChess plays random legal moves”.
• Games and positions: load and save PGN files, load FEN and EPD positions, set up a board by hand, and copy and paste games. The last 20 games are saved automatically.
• Opening books: a small built-in book and one based on ECO opening codes, plus Polyglot, CTG and ABK books you add yourself. Endgame tablebases (Syzygy and Gaviota) work too, if you copy them to the phone; none are included.
• Spoken moves in English, German or Spanish, off by default. There is no Chess960 mode.

The developer warns about battery use: when DroidFish keeps analysing in the background, or with long thinking times or pondering switched on, it “can use a lot of CPU power”, so exit with the back button when you aren’t using it.

What goes online

Nothing on its own. DroidFish has no update check, analytics or crash reporting. Its internet permission is used only when you choose an engine you set up yourself as a network engine, and then only to the computer you entered, in plain text.

About this file

• This is F-Droid’s build of DroidFish 1.90, compiled from the developer’s source, checked to build the same way again, and signed with F-Droid’s key. 1.90 came out on 25 February 2024; F-Droid published it on 5 March. It is the latest version: there have been no changes since, though the project hasn’t been declared finished.
• 1.90 updated Stockfish to version 16.1, released a day earlier, with its two neural networks, which is why the file grew to 65.8 MB. It also uses a faster Stockfish on newer ARM processors and keeps a fallback for older ones. From the code, the app copies the networks, about 69 megabytes, into its own storage the first time the engine starts, so it takes more space than the download.
• It runs on Android 4.1 and later, on ARM and x86, 32- and 64-bit. It still targets Android 9; Android only lets apps that target 9 or older run programs from their own storage, which is how DroidFish starts its engines. It declares 3 permissions: internet, vibration and storage. Our scan found no trackers.
• The app is translated into Portuguese, completely, in a mix of Brazilian and European wording.
• The screenshots are from DroidFish’s old Google Play listing, version 1.84 or earlier; there are no official screenshots of 1.90.

Licences

DroidFish is licensed under the GPL-3.0 (the source files say “or any later version”; F-Droid lists GPL-3.0 only), and Stockfish under the GPL-3.0. The in-app credits say only “Chess pieces from PyChess project” for the 17 piece sets; their origins, as far as we could trace them:

• Alpha, by Eric Bentzen: its original files say “Chess Alpha” is “free for personal non commercial use”.
• Chess Cases, the default set, and Leipzig, Alfonso, Magnetic, Maya, Pirat and Regular come from chess fonts that their source lists only as “Freeware”, with no licence text. Chess Cases isn’t credited in the app at all.
• Mérida is listed as freeware at its source and as GPLv2+ by Lichess.
• Chess Icons, Free Staunton and Metal Tops have no known source.
• Kilfiger is marked public domain in its own files, and the Wikimedia set comes from Wikimedia Commons under free licences.

The font for move notation carries both a public-domain note and the SIL Open Font License text. The move sound, off by default, came from a contributor in 2012 with no licence stated, and the source of the ECO opening data isn’t given.

CPU types in this build: arm64-v8a (64-bit ARM, almost every phone since 2017); armeabi-v7a (32-bit ARM, older and budget phones); x86 (32-bit Intel, emulators); x86_64 (64-bit Intel, emulators and Chromebooks).

Versions currently kept in the F-Droid repository. We host and check only the newest one. Full changelog.