Pinfu Yaku: The Full Requirements and Why Its Fu Is Always 30

Pinfu ("flat hand") is a 1-han yaku with more requirements than most other basic yaku, but once you know all of them, spotting a Pinfu opportunity becomes second nature.

Every Pinfu Requirement

• The hand must be closed (menzen).
• All 4 sets must be sequences (shuntsu) -- no triplets at all.
• The pair can't be a valuable tile (not a Dragon, not the round wind or your seat wind).
• The winning wait must be a ryanmen (open two-sided wait), not kanchan/penchan/tanki.

Why Pinfu's Fu Never Changes

Because every extra fu source (triplets, a valuable pair, a hard wait) is explicitly banned in Pinfu, its fu is always 30 on a Ron, and stays 20 (no +2 tsumo fu) on a Tsumo -- a specific carve-out in the fu system.

An example Pinfu hand -- every set is a sequence, and the pair (7 sou) isn't a valuable tile.