Last week, I mentioned that using a hammer would be a good test of power. Two responses were of great interest.
1. Dan Harden stated, "That is total nonsense and makes a mockery of thousands of years of martial knowledge."
2. Howard Popkin respectfully disagreed with me.
I suspect all the misunderstanding has to do with the suchness of language; i.e. its limits, how we so often project what we think others mean, and perhaps even how our "Pain Body" (history of painful emotional experiences) may even skew what we think the other fellow means.
Then, a couple of days ago I found this YoutTube of Okamoto's (Roppokai). It is in Japanese, and I do not speak Japanese, but the commentator appears to be stating the exact physical principles my example of "the hammer" was referring to at 4:20. The hammer strikes when you sequencially relax your muscle, have correct posture, and uke (or a nail or a large rock) is positioned well.
Personally, I hammer all day long like this without undue strain. I learned it from doing men and kesa cuts with my bokken.
Other simple (6th grade physics) mechanics thaqt I have trained as foundational principles in my aiki art are also presented on this clip as follows:.
1. 00.30 Raising the center of gravity
2. 4:20 Hammer dropping
3. 5:40 Whole body dropping (comes immediately before hammer dropping) allowing gravity to do its work.
4. 7:20 (Long Leverage) the longer the leverage (move from the bottom of your feet once you connect with uke's center of gravity) you can bypass uke's strength. This is the essence of a good float. I often name it "The law of similars". If I move from my wrist, I only collect your wrist. If I move from my elbow, I collect your elbow. If I move from my soulder, I collect your shoulder. If I move from the bottom of my feet, I collect your whole body.
Oh well, I hope that I sheds some light on this "hammer thing". Irencis is my goal, not polemics.