From Someya Sensei's book "Introduction to Shurikenjutsu" (手裏剣術入門) page 113:
Heiyo Waza
There is the combined use of shuriken with other weapons.
In this school, it is done in combination with the following five types of things (tachi, tanto (or shoto), hanbo, fundo kusari, and shuken). Of course it is possible to also be in combination with other weapons.
However, as its basis is iai (seated) and tachiai (standing) techniques, you must become proficient at the characteristic way of use of those techniques. That is to say, although the first strike is decided with the shuriken, for the second strike the unique usage (iai and tachiai techniques) is required. Then there is the problem of linking the first and second strikes.
This school has 20 kata for each heiyo waza, and I will introduce one representative technique from each respectively.
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I think Heiyo Waza is where shurikenjutsu comes alive. Although the book only has one example from each combination and most of the 20 kata mentioned for each combination have been lost to time, there is a lot that can be trained. Of course we have the Tōjutsu Heiyō Waza set of kata. Also moves from the Shodan Kata set can be done with various weapons as Heiyo Waza with shuriken. This can be done solo or as extended training with partner work. The applications become very broad from there and many training scenarios are possible with various points of focus.