Where the facts come from
Every factual claim on this site links to its source. This is the full list.
How we checked
Each fact was written alongside its source. Our build script stores the source text and, for every fact, checks that the key words and figures really appear in it. 90 of 90 checks passed when this site was last built (checked 3 Nov 2026). Where we couldn’t read a source, we left the claim out. We quote short phrases only, and never reproduce anyone’s diagrams or photographs. Board positions on this site are checked by computer.
Which rules we follow
The rules on this site follow the FIDE Laws of Chess, in plain words. Clubs and competitions can add their own rules, so for a tournament, read the FIDE Laws themselves and the organiser’s rules.
What we leave out
This is a beginner’s guide to the rules and the history of chess. It doesn’t cover tournament timing, ratings or openings. Where a source gives two dates or says something in two ways, we show both rather than pick one.
FIDE (the international chess federation) (1)
- FIDE Laws of Chess (46 facts)
Britannica (1)
- Britannica: chess (44 facts)
When sources disagree
Where sources give different dates or numbers, we show all of it, with links, and say how we handle it.
How old are the Lewis chess pieces?
- Britannica’s main text says the Vikings are believed responsible for 78 walrus-ivory chess pieces found on the Isle of Lewis in 1831, dating from the 11th or 12th century. Britannica: chess
- Britannica’s picture caption says the Lewis pieces were carved from walrus tusk ivory and whale teeth, are thought to be Norwegian, and date from the late 12th or early 13th century. Britannica: chess
How we handle it: Britannica’s chess article gives two dates. Its main text says the pieces date from the 11th or 12th century and calls them walrus ivory. Its picture caption says the late 12th or early 13th century, and walrus tusk ivory and whale teeth.