noun
pure double chow; two identical sequences
A mahjong hand containing two identical sequences (same numbers and same suit). Worth one han.
from Chinese yī bēi kǒu
一盃口は、同じ順子が二組ある手役です。
A pure double chow is a hand with two identical sequences.
この手は一盃口が付くから、もう一翻ある。
This hand has a pure double chow, so it's worth one more han.
Two sets of pure double chows, worth three han.
From Chinese 一盃口 (yī bēi kǒu), literally 'one cup mouth', a mahjong term.