The structure is the one seen irrespective of yawarakaboshi or kataboshi and by reinforcing hikae, the part from wrist to thumb cannot move freely and is likely to stabilize.
柔帽子、堅帽子の別なく見られる造りの一種で、控えを固める事によって手首〜親指根の自由が無くなり手首が安定しやすい。