Method

How the compendium is put together.

Where the pages come from

Every page here is generated from one set of data: the node tree, the bibliography, and the per-variant claims. Each fact is written once, so the pages can't disagree with each other.

Sources first, analysis after

The site carries two kinds of material and never mixes them. Sources are the documents: what each one is, where it can be read, and when it was checked. AI-generated material is what an AI model wrote from them: the confidence and evidence verdicts, the cross-comparison and its reading, the findings, and the summaries of sources added while cross-checking.

On a variant page the sources come first, on a solid gold rail. The analysis follows, below them, on a dashed grey-blue one, and every figure in it is footnoted back to a numbered source above. Other pages mark the same line the same way: the references are sources, the findings are analysis, and wherever the two meet on one page the analysis carries the badge. Where analysis and source disagree, the source is right.

Only what was read

A claim enters the data only if the source was fetched and read. Search-engine summaries don't count. A page that couldn't be opened is marked unreachable. Where a source contradicts itself, both readings are recorded. One entry wasn't read at source, and its page says so.

Confidence and evidence

Confidence is how good a variant's sources are. Evidence is whether they agree. A variant can have one good source, or several weak ones. Both are the analysis's verdicts, not properties of the sources, and are shown with the rest of it.

How sources are cited

Every variant page opens with its own numbered sources, ahead of any analysis, with the full citation, a link to the source itself, and a note on what it covers. Numbering is local to each page, so [1] on one variant is not [1] on another; each footnote names its entry in the bibliography, which indexes every source across the whole compendium. Each footnote also lists the other variants citing the same source, so you can see every variant that uses it.

A source is marked canonical where the chart drew the variant from it, supporting where the chart cites it alongside, and cross-check where it was checked afterwards to test the chart's claims.

Each source is also tagged with the kind of document it is, so a long list can be narrowed to the rules, the law or the history. The tag is the compendium’s classification, not part of the source:

Official rules

issued by the body or designer that governs the game

Tournament rules

the rules of one event, tour or league

Law

a statute, gazette notice or regulator’s rule

Rulebook

a published set of rules by an author with no authority over the game

Historical

written while the game it describes was being played

Scholarship

research by a historian, collector or academic

Journalism

a newspaper or magazine article

Encyclopedia

a general or specialist reference work, wikis included

Guide

a hobbyist’s explanation: FAQs, blogs, how-to pages

Forum

a discussion board or newsgroup

Commercial

published by a business: casinos, game apps, retailers

Organisation

a body’s own pages, other than its rules

Collection

a museum, library or archive’s catalogue record of an object

Where the analysis has said what a source contributes to one variant in particular, that note sits under the source, labelled for this variant. Where a kind of source was searched for and nothing was found, such as official rules or law, the variant’s analysis says so under Looked for, not found. Sources that were found but could not be read, because they are blocked, paywalled or in print only, are listed under Known, not yet read, and all of them are gathered on Missing sources. The family tree shows both counts for each variant: on hover, or in the sheet a tap opens on a phone.

A variant that has had a full pass under the search checklist also lists, under Where it was searched, the names it was searched under and every place the checklist names for its languages: national libraries, newspaper archives, statute databases, the search engines of each language, forums and video, with what each one gave, including nothing, and which could not be reached. What was not searched is said as plainly as what was.

Artwork

The tiles on the tool pages are FluffyStuff’s riichi tile set, in the public domain under CC0. The site’s icon is the scroll from Twemoji, © Twitter, Inc. and other contributors, licensed under CC BY 4.0.

What isn't included

Copyrighted rulesets: the NMJL and AMJA annual cards for any year, Mah Jongg Made Easy, and any variant's in-copyright rulebook. The rules are noted as facts, like tile counts, but the text of those works isn't copied.

Provenance vocabulary

For a collected file, in the ledger table:

| Value | Meaning | | --- | --- | | primary | The ruleset itself, from the body that issued it | | facsimile | A scan or verbatim reproduction of a primary source | | secondary | Someone's description or translation of a ruleset | | informant | An account of how a game is played, from a player, with no published rules behind it | | derived | Assembled from other sources, including anything reconstructed here | | unknown | Origin not established |

For a variant folder, in the README front matter and the root glossary:

| Value | Meaning | | --- | --- | | documented | A published ruleset or rule description exists and is cited | | catalogued | Listed in a variant catalogue with tile counts and hand sizes, but no rules text has been verified | | single-informant | The whole entry rests on one report from one person | | disputed | The descent shown is contested; the chart drew this link dashed | | placeholder | No source establishes the descent at all; the parent link is a guess | | lost | No rules text survives |

These describe the sources, not the game. placeholder means nobody has established where a game came from, not that the game is doubtful.