Thirteen Orphans
Also called: 國士無双, 十三么, Kokushi
A non-standard hand: all 13 unique terminal/honor tiles + a pair of one.
Thirteen Orphans is one of mahjong's classic limit hands. The structure: each of the 13 unique terminal/honor tiles (1m, 9m, 1p, 9p, 1s, 9s, plus all 7 honors) appears exactly once, plus a pair of one of them. Worth limit / yakuman in every variant that recognizes it. Riichi calls it Kokushi Musou; MCR and HK both at 88 fan / 13 faan; Taiwanese at 16 tai. Sichuan doesn't recognize it (no honors).
- Limit hand
A hand that hits the maximum table payout — typically the rarest and most beautiful.
- Yakuman
Riichi's limit hands — instant 13-han equivalent, payout capped at the table limit.
- Nine Gates
Concealed 1-1-1-2-3-4-5-6-7-8-9-9-9 in one suit + any tile of that suit. Considered the most beautiful hand.