How to Count Fu in Riichi Mahjong (Beginner's Guide)
Fu is the part of riichi mahjong scoring most beginners avoid for as long as possible. The rules are mechanical and only six things ever add fu; here is the complete walkthrough.
What is fu and why does it matter?
Fu (符, literally "tally") is the multiplier inside the base-point formula fu × 2^(han + 2). It only matters for hands below the mangan line (1-4 han); from 5 han up scoring jumps to fixed tiers and fu stops mattering. For low-han hands fu is what separates a 30-fu 2-han 2000-point ron from a 40-fu 2-han 2600-point ron. Most winning hands resolve to 30 fu or 40 fu after rounding.
What are the base values every fu count starts from?
Two pieces are always on the table. (1) Base 20 fu — every win except the special cases below starts here. (2) Winning method: tsumo adds 2 fu (except a pinfu tsumo, which keeps the 20). A closed-hand ron (menzen kafu) adds 10 fu. An open-hand ron adds nothing. After those, only triplets, kans, the wait shape and a yakuhai pair add anything more.
How much do triplets, kans and pairs add?
Triplets (koutsu): an open triplet of simples (2-8 of any suit) is +2 fu; an open triplet of terminals or honors is +4 fu; a concealed triplet (ankoutsu) doubles both — +4 fu for simples, +8 fu for terminals or honors. Kans (kantsu) multiply by four: open kan of simples +8, open kan of terminals/honors +16, concealed kan of simples +16, concealed kan of terminals/honors +32. The pair adds 2 fu if it is a yakuhai pair (your seat wind, the round wind or any dragon — round-and-seat double winds count 4 fu in some rule sets), otherwise 0. Sequences add nothing.
What about the wait shape?
Only single-tile or constrained waits earn fu. Tanki (single-tile pair wait), kanchan (closed-middle wait like 4-6 waiting on 5) and penchan (edge wait like 1-2 waiting on 3, or 8-9 waiting on 7) each add 2 fu. Ryanmen (two-sided wait like 4-5 waiting on 3 or 6) and shanpon (pair-on-pair wait) add 0. The wait shape fu only counts on the tile-group that actually completes the hand — pick the most fu-favourable interpretation if a hand can be read multiple ways.
When are pinfu and chiitoitsu special cases?
Pinfu and chiitoitsu both bypass normal fu math. Pinfu by definition has zero fu sources beyond base — closed hand, all sequences, ryanmen wait, non-yakuhai pair — so a pinfu tsumo is exactly 20 fu (no tsumo +2 in this case, that's the trade-off for the yaku) and a pinfu ron is exactly 30 fu (the 10-fu menzen kafu still applies). Chiitoitsu is always exactly 25 fu regardless of any other shape considerations. Both numbers are conventions baked into the formula; they are never rounded or adjusted.
Walk me through a worked example.
Closed hand: 234m + 678p + 234s + 111z (E wind triplet) + 99s pair, won by ron on the 3s (the kanchan wait closing 234s as a draw of 3 between 2 and 4 — actually that's a penchan-style read; let's say the win is the 5p closing a kanchan 4p-6p). The count: base 20 + menzen ron 10 + ankoutsu of honor 1z 8 + kanchan wait 2 + non-yakuhai pair 0 = 40 fu. With 2 han (riichi + yakuhai East), the base is 40 × 2^4 = 640; the non-dealer ron pays 640 × 4 = 2560, rounded up to 2600. The same hand by tsumo would add 2 more fu (42 → rounds up to 50).