You mean like this:
As opposed to like this:
It doesn't really matter, safety wise. The safety concerns seem to come from Americans more than from anyone else.
It does seem to be a weightier issue for Americans, more so than other countries. I have no idea why this might weigh heavier on the minds of Americans than non-Americans. Maybe you can chew over some of the reasons behind this and see which one tips the scales for you...
Having the heel pointed at the ceiling makes correct weight distribution harder.
It should be noted that if you do Tai otoshi the Adams way with feet like so:
That because of the dynamic nature of the throw you aren't actually planted when you do the technique and your heel is in fact raised slightly.
Only late on does the heel actually go flat.
For normal people who aren't built like stretch armstrong the lower you go the more the heel has to point upwards, this requires considerable skill to keep weight distribution from going wrong.
There's a bit on this in Adams' Tai Otoshi book, as I recall.
In the classic Japanese way, tori is up on the ball of his foot and the knee is pointing in towards tori's other leg. It's for safety as you say and you can also get a snap out of the knee to force uke over. Look at Paul Nogaki here at 1:36.
In the Adams/British way, tori is flat footed and both knees face forward. http://www.youtube.com/watch?v=t0BAmgezQWg
Yes, that is exactly what I mean. Thanks for the answer.
I'll stick with "when in Rome" and point my heal up when practising with the JJJ guys and not worry too much about it in judo.
PS I'm going to have killer triceps after all these push-ups
Thanks Res Judicata. I think I'm falling into the problem of training with two groups who do similar techniques differently. I'll have to have a look at Neill Adam's book, I think it's in the library in college.
The position of the other leg (leg uke doesn't go over) is also different between Adams and Nogaki. Adams' leg is very close to uke's while Nogaki is further out and angled. I've been shown the Adams distance and been corrected for the Nogaki one before.
Looks like there's still a whole lot about tai-otoshi I still haven't seen, let alone trained.
RJ pm me an e-mail address and I'll save you a trip to the library.
The problem I have with the heel up foot placement is that beginners struggle alot with correct weight distribution. See OP for explanation.
When you stand like this:
Its very hard to keep your hips square and facing forwards
Rather what happens is your hips get twisted around
And you end up with your hips angled off and away
If you combine this with poor tsurikomi i.e a beginner and a poor uke i.e another beginner.
Then the whole throw gets pulled out of alignment.
Add onto this premature head turn. See OP for full explanation.
And the result is you end up with the majority of the weight over the bent leg, rather than the throwing over leg.
So in a beginner you will sacrifice a negligible 'safety' benefit of a bent knee for a massive safety risk of having the hands fall behind the head and putting big strain on the shoulders, wrists and elbows as they're in a very weak structural position.
In randori this gets worse because it almost guarantees the beginner tori to be off balance backwards which the beginner partner will almost always seize upon as a chance for a tani otoshi, which is very dangerous and a much greater risk of injury than someone falling on your knee during a Tai otoshi.
The whole safety issue has to due with the outside leg being flat footed. In the "Adams" method, as pointed out, his heel is not flat until the end of the throw when any possibility of uke crushing tori knee is gone.
I was taught the whole spiel about keeping the heel up as well, I remember being lectured on it many times. I was also taught to put more weight on the inside leg (left leg in a RH throw), and very little on the outside leg. This is a very old form of Tai Otoshi, which makes sense, as my original sensei learned Judo from Japanese POW while a Marine Corps guard on Guam.
The real issue is as judoka uk pointed out: weight distribution of tori body which controls the direction of the throw and hence how tori transfers movement to uke.
Typically, beginners learn something like O Goshi or Seoi Nage (osoto gar as well, unfortunately for them). Weight is fairly even on both feet/legs, or at least is supposed to be.
But what usually happens is that the inside leg is favored with weight. When the student then moves (usually way too soon) to one leg throws like Uchi Mata or Harai Goshi, the inside leg is the support leg (jiko ashi), and tori bears the weight on that leg. The mistake is that in doing static uchikomi, tori balances both his and uke weight on the leg, whereas in the throw, there is no need to really do that for more than a fraction of a second, if at all.
So, when tori moves on to Tai Otoshi, there is a bias towards putting more weight on the inside leg, with the results being the common errors seen when teaching Tai Otoshi.
Imagine, you do hundreds or thousands of reps of throws where you are stopping and balancing on one leg, plus other throws like O Goshi, Seoi Nage, where you can bias the weight to the inside leg with no obvious ill effects.
Along comes Tai Otoshi, where you absolutely HAVE to shift your weight in the direction of the throw, and it seems impossible, because it feels totally wrong.
You really have to push with the tsurite in Tai Otoshi, but it's not so much pushing with your arm as pushing with your body through the arm.