Terminal

Terminals are the 1 and 9 tiles of each of the three numbered suits: 1m and 9m, 1p and 9p, 1s and 9s. They sit at the extreme ends of every suit's run, which gives them a distinctive role in both hand-building and scoring. Together with the honor tiles, terminals make up the 'terminals and honors' group that many special hands and bonuses are built around.

In play, terminals are awkward to use in sequences because they only belong to one possible run each: 1 can only sit in a 1-2-3 chow and 9 only in a 7-8-9 chow, whereas a middle tile like 5 fits three different sequences. This makes terminal waits narrower and terminal tiles common early discards. At the same time, terminals carry extra value: in Japanese riichi a triplet or kong of terminals earns more fu than one of simple tiles, and several yaku reward them. Tanyao (all simples) specifically forbids terminals and honors, while chanta and junchan require every set to contain a terminal or honor.

Across variants, terminals anchor prestige hands. Thirteen orphans (kokushi musou) needs one of each terminal and each honor plus a duplicate. All terminals (chinroutou) is a rare limit hand made entirely of 1s and 9s. In Chinese and Hong Kong scoring, outside hands containing terminals in every set are likewise rewarded.

For example, holding 7s-8s gives a two-sided wait on 6s or 9s, but if you instead hold 8s-9s you can only complete the run with 7s, a single-sided 'penchan' wait that includes the terminal 9s. That narrowness is precisely why terminals are both harder to use and more valuable when you do.