Terms & Privacy

CHA-Solver is a free, open-source algorithm that decides whether a chess position can still be won, and chasolver.org is where you can run it in your browser. In short: the algorithm is provided as-is, and this website collects almost nothing about you.

Last updated 23 June 2026

The algorithm

• CHA-Solver analyzes whether a chess position can still be won. Its verdicts are provided for informational purposes only, without any warranty of correctness or fitness for a particular purpose.
• A verdict is not an official ruling. In an over-the-board game, decisions under FIDE Article 6.9 and related rules rest with the arbiter. Please do not treat CHA-Solver as a substitute for their judgment.
• The algorithm is free software, released under the MIT License. You are welcome to read, audit, and reuse the code on GitHub.
• It is provided "as is". To the maximum extent permitted by law, the authors are not liable for any loss or damage arising from its use.

This website

The website that lets you run the algorithm in your browser has no user accounts and sets no tracking cookies. The little it does process is described here.

• IP address. Temporarily processed to rate-limit requests and prevent abuse. It is not written to our database and is discarded shortly after.
• Analyzed positions. The positions you analyze, together with their computed verdicts, may be saved to the public gallery. They are never linked to you.
• Tutorial answers. Recorded anonymously to help us improve the lesson.
• We do not sell or share any data with third parties.