Boshi has no tsuno inside to be reinforced, and the one without hikae is called 'yawarakaboshi' or 'waboshi', and the one where the back of the boshi is hollowed out is called 'fushinuki' to distinguish.
帽子に固めの角が入っておらず、控えが無いものを「柔帽子」或は「和帽子」、帽子の背の部分を刳り抜いてあるものを「節抜き」と呼び、区別している。