Lozza

A UCI Javascript chess engine with NNUE evaluation. Try her here:-

https://op12no2.github.io/lozza-ui/play.htm

Lozza was primarily created for use in browsers, but can also be used with traditional chess UIs via Node - and because of that, on pretty-much any platform.

Issues and Todo list: https://github.com/op12no2/lozza/issues

Basic use in a browser

All you need is lozza.js from release "Lozza 5" (not the repo itself - which will not work in a web environment and Lozza 5.1's web config is also broken.).

https://github.com/op12no2/lozza/releases/tag/5

Here is a little example to do a 10 ply search:-

var lozza = new Worker('lozza.js');

lozza.onmessage = function (e) {
  $('#dump').append(e.data);             // assuming jquery and a div called #dump
                                         // parse messages from here as required
};

lozza.postMessage('uci');                // lozza uses the uci communication protocol
lozza.postMessage('ucinewgame');         // reset tt
lozza.postMessage('position startpos');
lozza.postMessage('go depth 10');        // 10 ply search

Try this example here:-

https://op12no2.github.io/lozza-ui/ex.htm

Please note that Lozza's code is folded using {{{ and }}} (emacs convention) and most easily read using an editor with a folding capability.

More examples

A sister repo has more browser-based examples for playing and analysing etc. with Lozza.

https://github.com/op12no2/lozza-ui

You can try them here:-

https://op12no2.github.io/lozza-ui/play.htm

Play Lozza offline in chess user interfaces

Lozza can be used in popular chesss user interfaces like Banksia, Winboard, Arena and CuteChess via Node. Download the latest Lozza release and then follow the instructions in the wiki.

https://github.com/op12no2/lozza/releases

https://github.com/op12no2/lozza/wiki/Loading-Lozza-into-chess-user-interfaces

Acknowledgements

https://nodejs.org - Node

https://github.com/jw1912/bullet - bullet network trainer

https://www.chessprogramming.org/Main_Page - Chess programming wiki

https://computerchess.org.uk/ccrl/4040 - CCRL rating list

https://backscattering.de/chess/uci - UCI protocol

https://discord.gg/uM8J3x46 - Engine Programming Discord

https://talkchess.com - Talkchess forums

https://www.chessprogramming.org/Fruit - Early versions of Lozza used a HCE based on Fruit 2.1