National Treasures & Important Cultural Properties
of National Institutes for Cultural Heritage, Japan

It is written in Kokon-mokurokushō (Literature on Prince Regent Shōtoku), "[Among] the toys [Shōtoku had when he was] five or six-years old, the largest set was hitorimizutoridama (lit. fire-catching and water-catching stones), which include crystal, amber, board-game stones, water-jug-shaped ones and drop-shaped ones." These Hitorimizutoridama, then, were Shōtoku's toys when he was small, according to this passage.
　Hitorimizutoridama are small balls made of different materials such as amber or crystal, with a variety of shapes including round, rectangular or flat. Since there is a braided net attached to these balls, they are thought to have been used as accessories, like haigyoku (nephrite girdle pendants) in The Shōsōin Treasures. In Appendix of the Pictures of Hōryūji Treasures, there is a picture of them on a flower-shaped tray (N-42).
Ishinatoridama are crystal cubes stored in the lacquered container with a whirling pattern. They seem to have been used as beanbags for juggling games.