A shinai (竹刀) is a Japanese sword typically made of bamboo used for practice and competition in kendō. Shinai are also used in other martial arts, but...

(ōgi) A special characteristic of the school is the use of fukuro-shinai (袋竹刀), a bamboo sword wrapped in leather, said to have been developed by Kamiizumi...

by very fast waza. Both the uchidachi and the shidachi use fukuro shinai (袋竹刀) which explains the origin on the name. The third kata in the ryū, the Kodachi...