Master games: source and licence
Where the master games in Luftchess come from, the licence they come under, and what Luftchess changed.
The master games in Luftchess come from the Lichess broadcast database (https://database.lichess.org/#broadcasts), released by Lichess under the Creative Commons Attribution-ShareAlike 4.0 licence (https://creativecommons.org/licenses/by-sa/4.0/). Luftchess is not affiliated with or endorsed by Lichess.
Changes made by Luftchess: games are stored as published, byte for byte, with every tag, clock, evaluation and comment. Luftchess adds, beside them: duplicate games marked (the copy shown is the first published); games containing an illegal move marked and replayed only up to it; missing opening names filled from the Lichess chess-openings list (CC0); player names grouped by FIDE id; time-control classes derived from the tags and clocks; results, ratings and time controls indexed by position for the first 30 half-moves. When showing games, Luftchess may hide Lichess's automatic judgement comments by default (they stay in every download), adds source and licence tags to downloaded PGN, and withholds the names or games of people who asked to be removed.
The games are provided as-is, without warranties of any kind, as the licence says (section 5 of the legal code). You may reuse these games under the same licence. Months included: 2020-01-2026-09, imported 2026-10-02. Questions or removal requests: [email protected].