A rice hat, also known as 'asian conical hat', is a cone shaped hat made of straw or matting traditionally worn by rice harvesters in several asian countries. It is kept in place by a chin strap or an internal headband. It can be dipped in water and worn as an impromptu evaporative cooling device.
Very similiar to ajirogasa, a hat made of wicker or bamboo that generally does not have a chin strap.
A variant made of metal, wood or hardened leather and worn by soldiers is called jingasa.
This tag implicates hat (learn more).