Heavenly hand
If the dealer's fourteen opening tiles already form a complete hand, they declare a heavenly hand (tianhu, tenhou). No skill is involved, but it is a limit hand everywhere it is recognised.
Earthly hand
In Japanese rules, an earthly hand (chiihou) is a non-dealer winning by self-draw on their very first draw, before any calls. In Chinese rules an earthly hand often means a non-dealer winning on the dealer's first discard.
Odds
These hands are so rare that the name of the leading Japanese online platform, Tenhou, references the heavenly hand.
A reminder about luck
Mahjong's long-run outcome is decided by skill, but these hands are a reminder that any single game can turn on a lucky deal.
