Mario sensei compares the relative advantages of the chiishi versus tools like the kettlebell and Indian clubs, stating that chiishi are
heavier than Indian Clubs and allow the development of strength, but lighter than Kettle bells to allow more variation in the exercises that can be done. Chiishi design is similar to the Indian club which allows a greater range of motion. So to me I find Chiishi the “best of both worlds” as they say.
Mario sensei explains his own approach to strength training:
I alternate between modern weight lifting (barbell, dumbbells, & machines), body weight exercises and traditional weight lifting using Chiishi, etc.
I agree that body weight exercises are a staple exercise for the karateka, and in an ideal world I would alternate body weight exercises with traditional hojo undo equipment. I set out to do just that a decade back or so, and found that there was virtually no supply of products (in Australia), a very ill-defined training regime (outside select Gojuryu schools), a scarcity of instructors and a scarcity of books or videos on the topic. I wish that Mike Clarke sensei’s book The Art of Hojo Undo: Power Training for Traditional Karate was available then!
In my own search I came across the Russian Kettlebell. With an excellent training regime based on the approach from the pioneer of kettlebell training in the west, Pavel Tsatsouline (guest in episode 10 of The Applied Karate Show podcast), his books and videos and a ready supply of kettlebell products, I “got into the swing”. I undertook training (and later a kettlebell instructor course) with Don Stevenson.
I think that the kettlebell continues to be an awesome tool for a martial artists. The grip development, the off-centre centre-of-gravity, the range of compound exercises and the development of explosive power from the core make it suited to the needs of a karateka. These reasons are, as Mario sensei outlined, similar with hojo undo tools like the chiishi. But for me, the availability of product and the availability of quality instruction and instructional resources make the kettlebell my preference for strength training.