Also known as: 天使の小窓, 谷間ホール, 乳间缝隙, 纽扣缝隙
A small gap between the Buttons of a button-up Shirt, usually exposing a view of the character's Cleavage. The gap may be caused by a Popped Button, a Partially Unbuttoned shirt, or by a Taut Shirt tenting out due to the character's Bursting Breasts.
The shirt should still be buttoned above and below the breasts, and the breasts should not be fully exposed.
