From 合気道パーフェクトマスター, 2009 by Doshu

Doshu yonkyo omote nerve

Doshu yonkyo omote twist

Doshu yonkyo ura nerve

Doshu yonkyo ura twist

In the screenshots, pay attention to Uke‘s pinky finger to notice which arm Doshu is performing yonkyo on. In the DVD he demonstrates yonkyo omote on one arm, but yonkyo ura on the other arm. The screenshots are misleading as they look like they are done on the same arm.

As far as I can discern, Doshu presses on the same nerves for both yonkyo omote and ura.

Maybe it doesn’t matter. Maybe the key idea is to hold Uke‘s wrist like that of a bokuto.

Update: 2010.07.31 – After class tonight, K, Tak, Atsuko and I discussed and practiced yonkyo. We talked about maykubu (pulse-area) and toukotsubu (around the radial bone) and how Doshu discusses these two distinct-yet-close pressure points. We all agree the video is misleading visually, but when we take into account the points of the text, what Doshu says in other text, and when we actually practice omote and ura, we clearly understand that the pressure points are different. It is true that it feels more natural to press on toukotsubu when doing ura yonkyo, and of course myakubu when doing omote.

myakubu – 脈部
toukotsubu – とう骨部

Update: 2010.10.14 – Kobayashi Sensei describes myakubu in his treatment of sankyo omote.