The next video reveals a lot of principles used by Yamashima sensei for shomen uchi attacks.
1. Shomen uchi ikkyo. Yamashima uses arms to make center to center contact and uproots uke from underneath.
2. Shomen uchi irimi nage. Opening of the centerline to create centerline attack from behind uke.
3. Armpit closes and arms resemble boken like movements, but with relaxed intention.
4. During irimi nage Yamashima sensei uses the lower arm of uke to control uke's center.
5. Irimi nage "throw" is closing of centerline and release of tensile strength.
6. Yamashima sensei arms are used as antenna's. To feel and connect to his own center and uke's center.
7. Alternative irimi movements against shomen uchi attacks.
8. Arms are relaxed and therefore always "fall" naturally in front of his own center.
A lot of principles can and be studied using Youtube and can be experimented upon in your dojo with a partner.
Enjoy practice.