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Getting Started

This page describes how to install Lc0 for windows. If you just want to play Lc0 online, go here. TODO(Add link to other OSes when it’s written)


Lc0 has three parts:

NAME FILE Function Needed for Contributing Needed for Playing
Engine lc0.exe Does the tree search and calls the NN to get evaluations YES YES
Network (NN) Varies e.g. weights_run2_32930.pb.gz Stores the Neural Net’s evaluation function NO YES
Client client.exe Gets the latest network from the server, generates self-play games, and uploads the training data to the server YES NO
  • To help the project by donating GPU time, you engine and binary, and you should run client.exe. The client will automatically run lc0.exe, download the network for training, and ask the server what to do.

  • To play or analyze games with Lc0, you don’t need client.exe, but you do need the engine lc0.exe and a network file.


Engine and client

Download the engine and client as described here.


To install a network.

  • Download a network file.
    Refer to this page to decide the best network for your needs.
  • The name will be some long hash string, for example: b82f0b34b96c8f38f68ee97703b4149ab976122ca9bed6120f9dea88d733d266
  • Rename to “weights” or any other filename (for convenience, not necessary). No need to unzip the weights file!
  • Place the network file into the same directory where the lc0 application is located.
  • The file will be found automatically by Lc0.
    Note that if there are several network files in the directory, Lc0 will use the latest one by file modification date.


The best way to play and analyze games is to use chess GUI. Check this document to find how to do that.

Contribute training games

Running self-play games is how Leela learns. To contribute games, simply run the client program on your computer. The client automatically downloads the latest net from the training server, generates self-play games with that net on your local machine, and uploads these games back to the training server.

Note: Leela only learns from games generated by running the client. In particular, games run with a GUI don’t get uploaded to the training server.

Information about advanced configuration can be found here.


If you have any questions or issues, it’s recommended to join the discord for quick help, it is usually very active. If you prefer to debug stuff by yourself, troubleshoot page may help.