soft, crumpled, unlacquered eboshi (headwear)
Historical term for a soft, unlacquered eboshi often worn by soldiers under helmets from the Kamakura period onward. The name comes from its crumpled, informal appearance.
See also: 烏帽子
Warriors of the Kamakura period sometimes wore a soft eboshi under their helmets.
烏帽子 is the general term for the lacquered formal headwear; 揉烏帽子 is specifically the soft, unlacquered variant.
From 揉み (momi, 'crumpled, softened') + 烏帽子 (eboshi, 'formal headwear'). The exact historical derivation is uncertain, but the name reflects its soft, informal nature.