A question came up the other today about the difference between the words "tenkan" and "tenkai" which I think gets confused at times. As far as I understand it...
Tenkan 転換 breaks down as:
転 suddenly, quickly
換 change, alter, substitute
and together 転換 as convert or divert
You might think of it as changing direction suddenly, or diverting uke's energy. In aikido, it refers to a turning movement (tenkan ashi), usually 180 degrees:
Tenkai 転回, however, breaks down like this:
転 suddenly, quickly
回 turn, rotate, revolve
and together 転回 as revolution or rotation
In much of the aikido world, it refers to a form of movement, what we commonly call a "hip switch", where you turn 180 degrees but without moving our feet (we do it in the Walking Kata, but there it's called "ude goshi gaeshi" or arm-hip reversal, which frankly is probably more clear):
Both tenkan and tenkai are part of what's called tai sabaki or methods of moving the body.
Okay, ukemi isn't really a new cardio craze—but why not?
I remember when I first started aikido years ago, just prior to my 20th birthday. I was a good 20 or 30 pounds overweight (I'd been that way since hitting puberty), and made no other lifestyle changes other than attending aikido classes 3 times a week.
I remember the ukemi practice we did at the beginning of every class kicking my ass. Fall down, get up again, fall down, get up again, fall down, get up again. Backwards, forwards, sideways... I think I lost 10 pounds or more in the first several months just from that!
The problem is, the older I got, and the more advanced I became, the more I started "leading" classes instead of "doing" them. Ukemi practice was gradually replaced by sitting around, watching everyone else, drinking coffee and giving input when needed.
And I'm paying for it. My lifestyle in general has slipped and I'm probably in the worst shape of my life (and that's saying…
I'm a graphic designer by trade, so occasionally I get the uncontrollable urge to redesign various bits of info pertinent to budo when I get a spare moment. Here's a reference chart of "kyusho" or vital points taken from Pascel Krieger's seminal book on Shindo Muso Ryu Jodo, "The Way of the Stick."
Feel free to use this JPEG however you like. If you prefer a scaleable PDF, you can download it here.