八やつ口くち

noun

small opening under the sleeve of traditional Japanese clothing

Refers to the slit or opening where the sleeve meets the bodice, below the armpit, found in garments like kimono or yukata. A specialized term used mainly in the context of traditional clothing.

• 着き物ものの八やつ口くちから風かぜが入はいって涼すずしい。

  The breeze comes in through the opening under the sleeve of the kimono, making it cool.

• 八やつ口くちの縫ぬい方かたが少すこしほつれている。

  The stitching of the underarm opening is coming undone a little.