Natsuo koshirae, commission for the Meiji Emperor.

In 1872 in particular Natsuo received a commission from Emperor Meiji to make mounts for the meibutsu Ryusuiken sword, at the time 1,200 years old and thought to be the property of Emperor Shomu. The sword was taken out of the Shosoin repository and Natsuo made its koshirae. After this the name of the sword was changed to Suiryuken due to the fantastic mounts with dragons and waves he made for the blade. The blade is now Juyo Bunkazai.