onward, the transplanted thread!
I like to do Sanchin stepping with a partner resisting me using a fist on my chest, abdomen, shoulders, sternum, and even forehead (that's a tough one!)
It's difficult to keep the whole body focused and tucked and really be able to step through strongly.
For me, it's a great drill to practice anytime.
Recently I was called upon to teach a new student for an entire class and I used this as an element, it was very useful.
I had to explain how to "roll under" the resistance, and demonstrate it myself, and then get the student to start doing it. It was fun, interesting, challenging and useful, and the student felt some accomplishment, which to me is one of the most important elements of a class.
I really believe it's one of our "old-school" fundamentals.
The music spoke to me. I felt compelled to answer.