MCR Mahjong Calculator
Score Chinese Official (Mahjong Competition Rules / WMSC) hands with full 81-fan detection, automatic exclusion rules, kong and concealment tracking, and the 8-fan minimum. Tap tiles, mark your winning tile, and see the breakdown — including which patterns excluded which.
8 tiles away from tenpai.
The final tile you add becomes the winning tile.
What is Chinese Official (MCR) mahjong?
MCR — short for Mahjong Competition Rules, also known as Chinese Official or WMSC mahjong — is the international tournament ruleset adopted in 2002 by the World Mahjong Sports Games. It’s the variant used at the World Mahjong Championship and most major international tournaments today.
MCR is more precise than the regional variants: every winning hand is scored by combining patterns from a canonical list of 81 fan (番), ranging from 1 fan for a Single Wait up to 88 fan for limit hands like Big Four Winds and Nine Gates. Strict exclusion rules prevent double-counting when a higher-fan pattern implies a lower one — for example, Pure Straight automatically suppresses the two Short Straights inside it.
To declare a win you need at least 8 fanfrom scoring patterns alone (flowers and wind bonuses don’t count toward the minimum). If your hand happens to have a valid winning structure but no scoring patterns at all, the Chicken Hand rule awards 8 fan so the win still counts.
The 81 fan patterns by tier
Every MCR fan rule with its point value. Tap any pattern for the rule, a worked example, and related patterns at the same tier.
Scoring a 5-fan hand
The hand below combines four patterns. By itself it doesn’t clear the 8-fan minimum, but it shows how the calculator surfaces every pattern that applies — useful for learning the rules even when you can’t declare.
winCommon MCR scoring questions
What is MCR mahjong?+
MCR — Mahjong Competition Rules, also called Chinese Official or WMSC — is the ruleset used at the World Mahjong Sports Games and most international tournaments since 2002. It uses 81 distinct fan (番) scoring patterns ranging from 1 fan (e.g. Single Wait) to 88 fan (limit hands like Big Four Winds and Nine Gates).
Why is the 8-fan minimum important?+
MCR requires every winning hand to score at least 8 fan from its scoring patterns alone — flower tiles and the dealer/wind bonuses don't count toward the minimum. If a hand wins but scores fewer than 8 fan, it can't be declared. The Chicken Hand rule awards 8 fan if a hand has no other scoring patterns, so a valid win never collapses to zero.
How does the calculator handle multiple decompositions?+
Some hands can be parsed in more than one way (for example, 234m·234m·234m can be three identical chows or three consecutive pungs). The calculator tries every legal decomposition — standard, Seven Pairs, Thirteen Orphans, knitted variants, and Nine Gates — and picks the one with the highest total fan, after applying WMSC exclusion rules.
What exclusion rules does the calculator apply?+
MCR uses the WMSC implication table: when a higher-fan pattern fully includes a lower one, the lower one is suppressed to avoid double counting. For example, Pure Straight (16 fan) excludes the two Short Straights inside it; Four Concealed Pungs (64) excludes All Pungs (6) and Three Concealed Pungs (16). The calculator applies these automatically.
Do flowers and seat / round winds score?+
Yes — flower tiles score 1 fan each, a pung of your seat wind scores 2 fan, and a pung of the prevailing round wind scores 2 fan. To get these credited you need to enter the round and seat context in the calculator settings. They don't count toward the 8-fan minimum, though.
How is MCR different from Hong Kong and Riichi?+
Hong Kong mahjong uses ~27 faan patterns and pays out exponentially (2 to the power of faan). Japanese Riichi uses han and fu with totally different yaku and a 1-han minimum to declare. MCR is the most precise — 81 fan patterns, strict exclusion rules, 8-fan minimum, and no luck-based bonuses like dora.