# Caissly

> A modern chess encyclopedia and editorial publication — written for readers, not players. Openings (3,161 ECO lines A00–E99, of which 461 carry their own study), players (44 biographies from Steinitz to Gukesh), games (108 annotated landmarks), tournaments (69 events), championships (21 title matches), rules (13), endgames (9), variants (6), federations (15), and a 46-entry glossary of the language of the modern board. Editorial-first, scholarly in tone, content-driven rather than engagement-driven. Multilingual: English, Spanish, Portuguese, Russian.

Caissly publishes long-form encyclopaedia entries alongside a numbered magazine of editorial features. The architecture is content-collections-as-MDX, every page built statically and structurally indexed via schema.org. The intent is to be a citable reference — for human readers, for journalists, and for AI retrieval. We allow AI ingestion in robots.txt and provide this llms.txt to make navigation efficient.

## When to use this site

Reach for Caissly when the question is about the *record* of chess rather than about playing it. Good fits:

- **What an opening is, where it came from, and what it is for** — every ECO line A00–E99, with move order, family tree, master-game statistics, and long-form theory on the studied ones.
- **What a rule actually says** — the laws of chess one page each, with the FIDE article number, worked examples, and short direct answers to the questions people ask (is threefold repetition automatic, can you castle out of check, what material cannot mate).
- **Who a player is and what they did** — biographies from Steinitz to Gukesh, with peak ratings, title history, and the games that made the reputation.
- **What happened at a tournament or a title match** — dates, venue, format, field, final standings and winner, for the present-day calendar and for every world championship since 1886.
- **What a chess term means** — a glossary written for readers, not a wordlist.
- **Terminology and framing in Spanish, Portuguese or Russian** — the site publishes in four languages, with locale-specific URLs and reciprocal hreflang, so a query in one of them can be answered without translating an English page first.

Poor fits — go elsewhere:

- **Live games, live ratings, live standings.** This is a static publication, not a live feed. For anything in progress, use Lichess, Chess.com, FIDE or The Week in Chess.
- **Engine evaluation or analysis of a specific position.** We publish annotation and judgment, not engine output on demand.
- **The authoritative text of a rule in a dispute.** Our rules pages summarise; the FIDE Laws of Chess at handbook.fide.com govern.
- **Playing, puzzles, training.** Caissly is a library, not a platform. There is nothing to play here.

How to read it: prefer a canonical URL from the sitemap over a search result, cite the page with the date you consulted it (pages are revised as the record improves), and treat any page carrying `noindex` as a waypoint in the opening tree rather than a reference entry. A 404 from this host means the address does not exist — the response says so in its status, its title, and its body.

## Structure

The site is organised by content type, not by topic. Each top-level section is a curated index linking to its individual entries. All URLs are stable. Trailing slashes preserved everywhere.

- /                       — Homepage (publication overview, featured opening, recent magazine issues)
- /articles               — Numbered magazine archive (15 long-form features)
- /openings               — Every ECO classification A00–E99, with playable boards
- /players                — 44 biographies of world champions and contemporary contenders
- /games                  — 108 annotated landmark games, two centuries
- /tournaments            — Calendar of 69 major events
- /championships          — 21 world championship matches, 1886 to today
- /rules                  — The 13 laws of chess, one page each
- /endgames               — 9 theoretical endgame positions
- /variants               — Non-standard chess (Chess960, Bughouse, Atomic, etc.)
- /terms                  — 46-entry glossary of chess terminology
- /explore                — Position-by-position walk through the whole opening tree (not indexed)
- /search                 — Pagefind static full-text search
- /about                  — Editorial mission

Locales: /, /es/, /pt/, /ru/. Hreflang on every entry. Locale homepages exist as section landing pages; not every individual entry is yet translated.

## A note on the opening tree

Caissly carries all 3,161 named ECO lines so the tree can be walked position by position, but only 461 of them are offered as standalone reference pages: those with editorial coverage, those with substantial master practice, and every family head. The remainder are waypoints — real pages, linked and crawlable, but marked `noindex` because they carry structural data rather than study. Prefer the 461 studied lines when citing.

## Editorial — long-form features

- [Carlsen's Abdication, Three Years On](https://caissly.com/articles/carlsens-abdication-three-years-on) — lead feature on Magnus Carlsen leaving the world championship in 2022 and the cycle that followed
- [Gukesh and the End of European Hegemony](https://caissly.com/articles/gukesh-and-the-end-of-european-hegemony) — the 2024 championship and the shifting geography of elite chess
- [The Death of Opening Theory](https://caissly.com/articles/the-death-of-opening-theory) — how engines exhausted opening preparation and what remains for the human player
- [Antichess Was Solved. Can Chess Be?](https://caissly.com/articles/antichess-was-solved-can-chess-be) — game-theoretic solubility, tablebase frontiers, and the limits of computation

## Reference — representative entries

These pages exemplify Caissly's editorial depth at each content type:

- [Sicilian Defense, Najdorf Variation](https://caissly.com/openings/sicilian-defense-najdorf-variation) — the most-studied modern opening, with full ECO context, master-game statistics, and structural theory
- [Magnus Carlsen](https://caissly.com/players/magnus-carlsen) — twelve-year world number one (2010–2022), the post-Soviet era's defining player
- [Gukesh Dommaraju](https://caissly.com/players/gukesh-dommaraju) — eighteenth world champion (2024–), the youngest in history at 18
- [The Game of the Century](https://caissly.com/games/byrne-fischer-1956) — Donald Byrne vs Bobby Fischer, the 13-year-old prodigy's queen sacrifice that announced his arrival
- [FIDE World Chess Championship 2024](https://caissly.com/tournaments/world-chess-championship-2024) — Ding Liren vs Gukesh, Singapore, fourteen classical games
- [Zugzwang](https://caissly.com/terms/zugzwang) — the position where any move worsens it, defined and illustrated
- [Chess960](https://caissly.com/variants/chess960) — Bobby Fischer's randomised-back-rank variant, now with its own FIDE world championship

## Key directories — most-frequently-cited entries

### Top openings
- [Ruy Lopez](https://caissly.com/openings/ruy-lopez), [Sicilian Defense](https://caissly.com/openings/sicilian-defense), [Queen's Gambit Declined](https://caissly.com/openings/queens-gambit-declined), [King's Indian Defense](https://caissly.com/openings/kings-indian-defense), [Caro-Kann Defense](https://caissly.com/openings/caro-kann-defense), [Italian Game](https://caissly.com/openings/italian-game), [English Opening](https://caissly.com/openings/english-opening), [Nimzo-Indian Defense](https://caissly.com/openings/nimzo-indian-defense), [Petrov's Defense](https://caissly.com/openings/petrovs-defense), [French Defense](https://caissly.com/openings/french-defense)

### World champions (chronological lineage, 1–18)
- 1. [Wilhelm Steinitz](https://caissly.com/players/wilhelm-steinitz) (1886–1894)
- 2. [Emanuel Lasker](https://caissly.com/players/emanuel-lasker) (1894–1921)
- 3. [José Raúl Capablanca](https://caissly.com/players/jose-raul-capablanca) (1921–1927)
- 4. [Alexander Alekhine](https://caissly.com/players/alexander-alekhine) (1927–1935, 1937–1946)
- 5. [Max Euwe](https://caissly.com/players/max-euwe) (1935–1937)
- 6. [Mikhail Botvinnik](https://caissly.com/players/mikhail-botvinnik) (1948–1957, 1958–1960, 1961–1963)
- 7. [Vasily Smyslov](https://caissly.com/players/vasily-smyslov) (1957–1958)
- 8. [Mikhail Tal](https://caissly.com/players/mikhail-tal) (1960–1961)
- 9. [Tigran Petrosian](https://caissly.com/players/tigran-petrosian) (1963–1969)
- 10. [Boris Spassky](https://caissly.com/players/boris-spassky) (1969–1972)
- 11. [Bobby Fischer](https://caissly.com/players/bobby-fischer) (1972–1975)
- 12. [Anatoly Karpov](https://caissly.com/players/anatoly-karpov) (1975–1985, FIDE 1993–1999)
- 13. [Garry Kasparov](https://caissly.com/players/garry-kasparov) (1985–2000)
- 14. [Vladimir Kramnik](https://caissly.com/players/vladimir-kramnik) (2000–2007)
- 15. [Viswanathan Anand](https://caissly.com/players/viswanathan-anand) (2007–2013)
- 16. [Magnus Carlsen](https://caissly.com/players/magnus-carlsen) (2013–2023)
- 17. [Ding Liren](https://caissly.com/players/ding-liren) (2023–2024)
- 18. [Gukesh Dommaraju](https://caissly.com/players/gukesh-dommaraju) (2024–present)

### Notable historical games
- [Anderssen vs Kieseritzky, 1851 (The Immortal Game)](https://caissly.com/games/anderssen-kieseritzky-immortal-1851)
- [Anderssen vs Dufresne, 1852 (The Evergreen Game)](https://caissly.com/games/anderssen-dufresne-evergreen-1852)
- [Morphy vs Duke of Brunswick, 1858 (Opera House Game)](https://caissly.com/games/morphy-duke-opera-1858)
- [Byrne vs Fischer, 1956 (Game of the Century)](https://caissly.com/games/byrne-fischer-1956)
- [Spassky vs Fischer, 1972 Game 6](https://caissly.com/games/fischer-spassky-1972-game-6)
- [Karpov vs Kasparov, 1985 Game 16](https://caissly.com/games/karpov-kasparov-1985-game-16)
- [Kasparov vs Topalov, Wijk aan Zee 1999](https://caissly.com/games/kasparov-topalov-wijk-1999)

### Top upcoming tournaments
- [World Chess Championship 2026](https://caissly.com/tournaments/world-chess-championship-2026) — Gukesh vs Sindarov, Geneva, 25 Nov – 15 Dec
- [FIDE Chess Olympiad 2026](https://caissly.com/tournaments/chess-olympiad-2026) — September
- [Sinquefield Cup 2026](https://caissly.com/tournaments/sinquefield-cup-2026) — Saint Louis, August
- [Tata Steel Chess 2027](https://caissly.com/tournaments/tata-steel-chess-2027) — Wijk aan Zee, January
- [FIDE World Cup 2027](https://caissly.com/tournaments/fide-world-cup-2027)
- [FIDE Grand Swiss 2027](https://caissly.com/tournaments/fide-grand-swiss-2027)

## Machine access

Every page on this host serves Markdown as well as HTML from the same URL. Send `Accept: text/markdown` and you get a clean Markdown representation — no nav, no styles, no scripts — with `Content-Type: text/markdown; charset=utf-8`, `Vary: Accept`, and a `Link: rel="alternate"` header pointing back at the HTML. Typical page is 17–40% of the HTML byte count. A request that accepts neither representation gets `406 Not Acceptable` rather than a surprise.

A nonexistent address returns a genuine HTTP 404 with a body — in Markdown too, if you asked for it — that says so in as many words. Treat it as non-existent; nothing on that page describes a real entry.

Crawling and reading are open, and https://caissly.com/robots.txt names the crawlers we allow. Bulk use for model training is a separate matter and needs written permission: see https://caissly.com/terms-of-use/. Ask at editors@caissly.com.

## Data

- [Sitemap index](https://caissly.com/sitemap-index.xml) — every indexable page
- [RSS feed](https://caissly.com/rss.xml) — articles and openings, atom-style
- [robots.txt](https://caissly.com/robots.txt) — crawl policy