Fu Calculation (符計算)

13.1 What Is Fu?

Fu (符) is the secondary scoring component that reflects the specific composition of a winning hand. While han measures the "quality" of your yaku, fu measures the structural details: what types of melds you have, what your wait type was, how you won, and what your pair is. Fu is always rounded up to the nearest 10. For hands worth 5+ han, fu becomes irrelevant (the score jumps to fixed mangan/haneman tiers). Fu matters most for hands in the 1-4 han range, where it can significantly affect the final score.

13.2 Fu Calculation Components

Base Fu (副底)

The base is always 20 fu. A closed hand winning by ron adds 10 fu (for a starting total of 30). A tsumo win adds 2 fu. An open hand winning by ron gets only the base 20 fu.

Meld Fu (面子の符)

Sequences contribute zero fu. Only triplets and kans add fu, with the amount depending on whether the meld is open or closed and whether the tiles are simples or terminals/honors. Closed terminal kans (32 fu) are the highest single meld contribution and are exceptionally rare.

Wait Fu (待ちの符)

Pair Fu (雀頭の符)

13.3 Special Cases

Pinfu (平和): Pinfu is defined as a hand with 0 fu from structure (all sequences, ryanmen wait, non-yakuhai pair). When won by ron, it is 30 fu (20 base + 10 closed ron). When won by tsumo, it is fixed at 20 fu by convention—the normal +2 tsumo fu is waived to maintain pinfu's identity as a "0 fu hand." This 20-fu tsumo case is the only time fu can be 20.

Chiitoitsu (七対子): Always fixed at 25 fu, regardless of tile composition. This is the only time fu is not rounded to a multiple of 10.

Open hand with no fu features: An open hand of all sequences, ryanmen wait, non-yakuhai pair, winning by ron would calculate to 20 fu base + 0 from everything else = 20 fu. Since pinfu requires a closed hand, this is NOT pinfu. By convention, this is rounded up to 30 fu (some sources state this as a rule; others handle it through the general "minimum 30 fu for non-pinfu-tsumo" convention).

13.4 Worked Example

13.5 Fu Memorization Tips

Most hands fall into common fu patterns. Rather than calculating every hand from scratch, experienced players recognize patterns:

30 fu: All-sequence hands (pinfu-like structures) won by closed ron; or simple open hands.

40 fu: One closed triplet of simples added to a 30-fu base, or a kanchan/penchan/tanki wait on a closed-ron hand.

25 fu: Chiitoitsu only.

For 5+ han hands, don't bother calculating fu—it doesn't affect the score.

13.6 Fu in Practice — Common Patterns to Memorize

Rather than calculating fu from scratch every time, experienced players memorize the most common fu outcomes. Ide Yousuke (井出洋介), in his scoring guides published through multiple editions, recommends memorizing these patterns:

For hands at 5+ han, fu does not affect the score (it is mangan or above regardless), so calculating fu is unnecessary. The practical significance of fu is primarily for 1-4 han hands, where the difference between 30 and 40 fu (or 40 and 50) can change the payment by 25-50%.

13.7 Beginner Exercise — Calculate the Fu