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.

h4. Examples

* !post #6378691
* !post #4434758

h4. See also

* [[center opening]]
* [[cleavage cutout]]
* [[partially unbuttoned]]
* [[popped button]]
* [[unbuttoned shirt]]
天使の小窓