Sources & how this guide is written

Primary references

• The National Mah Jongg League (NMJL) — the governing body founded in New York City in 1937. Publisher of the annual Official Standard Hands and Rules card and the authority on legal hands, joker restrictions and tournament procedure.
• The annual NMJL card — the definitive list of legal winning hands for the year in play, including each hand's printed point value, its concealed or exposed status, and any no-joker restriction.
• Standardized National Mah Jongg Tournament Rules — the codified tournament standard used at organized events across the United States and Canada.
• The American Mah-Jongg Association (AMJA) — the second annual card publisher. Mentioned where the choice of card affects play.
• Published reference works on American mahjong — used to cross-check tile composition, Charleston procedure, scoring convention and the historical record from the 1920s craze onward.

Where to verify it yourself

Every rule stated on this site can be checked against a primary source. These are the ones we work from — rule-making bodies and published rule documents, never shops or paid services:

External links last verified 2026-09-14. The five primary sources above are re-checked monthly. Two are versioned files that can move: the masterpoints tournament rules carry the R8 edition tag, and the MahjLife sheet is dated 2023/06 — if either is retired we update the link here and on every page that cites it.

• National Mah Jongg League (NMJL) — the official card, the final authority at any table. The card defines the legal winning hands; the League’s own booklet Mah Jongg Made Easy covers the full game procedure, and disputed rulings are settled by the League.
• American Mah-Jongg Association — official rules — the second annual card publisher. A readable restatement of NMJL-aligned play: walls and dealing, the Charleston, calling, exposures, joker restrictions, dead hands, and the conditions for declaring Mah Jongg. Their beginner guide covers equipment and tile composition.
• Standardized National Mah Jongg Tournament Rules (R8) — the codified tournament standard used at organized events: card on display, zero tolerance, East and deal, score verification, the tightened Charleston, no pick-ahead, and the blind-pass penalty.

Our own deep dives

Where the standard rules meet the situations that actually cause arguments, we work them through in full:

• Rulings & case library — dead hands, the not-viable call, the window in which an exposure can still be corrected, contested discards, and the exact joker exchange procedure.
• The Charleston: a decision manual — pass order, blind passes, the second Charleston, the courtesy pass, and how to read the nine tiles that move before play begins.
• The 2026 NMJL card: what actually changed — the PKPK → PPKK shift, the return of the sextet after twenty years, and what both do to your opening.
• Tournament play — seating, the tightened Charleston, calling discipline, score verification, bonuses/penalties, table rotation, and the major championships under the Standardized National Mah Jongg Tournament Rules.
• Rule variants: NMJL, Wright-Patterson & AMJA — how the three American families differ in tiles, jokers, valid sets, and scoring.
• Defensive play — reading exposures, safe vs. danger tiles, counting jokers, and when to fold.

Where a primary source runs out

Some questions have no rulebook answer — how a club actually calls a disputed tile, what a variant tradition does, what a defensive principle is worth in practice. Where we lean on a long-standing outside reference rather than a rule document, it is named here. Nothing on this page links to a shop, a marketplace or a paid service.

• MahjLife Mini-Tournament Rules (2023) — a published rule sheet for representative event bonuses and penalties (self-draw +10, no-joker +20, dead 0, feeding a ready hand −10/−20/−25) and table rotation schemes.
• Tom Sloper — American mahjong FAQ — a long-running, independently maintained reference covering NMJL rules, the card, jokers, calling windows and table etiquette. Cited as an independent authority: not affiliated with the League, and not a retailer.
• Variant traditions and public wikis — the Wright-Patterson and AMJA variants are described from each tradition’s own published rule material. Public wikis and community references are consulted only to cross-check a point where the primary sources are silent, and never used as the sole basis for a rule statement.