涼帽
Any headwear that atypically leaves the crown of the head exposed, either by design or due to [[torn hat|damage]].

Note that this excludes headwear that already has applicable terminology on Danbooru - such as [[visor cap]]s being the 'open' variant of [[baseball cap]]s. 

One example of an open hat is the [[chinese clothes|traditional Chinese]] "Cooling hat"/"Hakka hat" (<i>Liangmao</i>). This bears resemblance to [[ajirogasa]], with the exception of a circular cutout in its middle. This modification is applied to keep the wearer's head cool in hot weather.

[tn]Other terms: <i>capless hat</i>, <i>half-hat</i>, <i>topless hat</i>[/tn]
open hat