Revisiting this after a few more years of practice... I noted Kevin Wilbanks' comment about why going straight for uke's wrist might not be practical. However, I also received instruction from the late Sugano Shihan in which he explicitly indicated that O Sensei taught just that: your 'gyaku' hand goes straight to uke's striking wrist, by contrast with ikkyo in which it goes to uke's striking arm, just above the elbow. (As I noted, Yamada Shihan, who was Sugano's co-instructor at New York Aikikai, also demonstrates the 'straight to the wrist' way of applying shomen uchi nikyo ura).
The only suggestion I have about reconciling this with Kevin's comment is as follows: if you were only using your 'gyaku' hand, I would entirely agree with Kevin - you'd have to have reflexes like a snake to grab a full-speed shomen before it reached you. However, the key may be in the use of your 'ai' hand, which - after all - is meant to be intercepting and blending with uke's strike before you attempt to gain control with your 'gyaku' hand. Louis van Thieghem Shihan uses a very interesting exercise for shomen uhci ikkyo, in which nage has his/her eyes closed (!)... one thing it definitely teaches you is the role of the 'ai' hand in providing tactile guidance to your 'gyaku' hand without the need to look at uke's strike...
I hope this helps. The learning process continues... probably indefinitely ;-)
Last edited by racingsnake : 07-17-2012 at 10:28 AM.