Sanankou (Three Concealed Triplets)

Riichi declared on the very first uninterrupted turn — no calls have happened yet. Closed-only. 2 han instead of riichi's normal 1, with the ippatsu window starting the same turn so the bonus-han chance is the highest of any riichi variant.

A closed hand of exactly seven distinct pairs. The seven pairs must all be different tiles — duplicates of the same pair count as one. Scores a flat 25 fu and pairs well with honor-heavy or mixed-suit hands that resist forming triplets.

The same numerical sequence in all three numbered suits (e.g., 234m / 234p / 234s). 2 han closed, 1 han open. Often paired with pinfu or tanyao, and structurally exclusive with ittsu — pick one or the other based on whether your early draws cluster vertically or spread horizontally.