Many weeks ago something subtle caught my attention. We did katatedori sumi-otoshi as a simple class demonstration and all went well, except when I drew the perpendicular line very slowly behind his legs to show someone, my aite stepped back a little – just a little.

It makes sense that the perpendicular line drawn between Uke‘s feet (from his heels) towards his rear must be precisely 90 degrees to prevent either leg from stepping back (it is kinda funny to watch Uke fall over backwards while being unable to step at all, and land on his seat.)

However, you can’t just draw a line straight back because Uke‘s body is in the way. You need to draw a curve around Uke to reach his rear perpendicular line to trace it. Because of this, it is natural to draw a line straight back, but not at 90 degrees. If Uke blends, he will allow himself to fall. If it is a person unfamiliar with the art, he may step back with his rear leg to adjust his balance. This is what I noticed.

New intermediary goal

The extension of Uke‘s arm should instead have a new intermediary goal: to shift balance to Uke‘s back leg – the leg Uke likes to step back with. This prevents Uke from kicking you with his back leg which is a danger otherwise. This angle should be drawn along the imaginary line connecting Uke‘s feet. Sometimes Uke‘s front leg will come off the ground like a tembin.

Once his balance has been shifted safely, Nage’s extension of Uke‘s arm can then go behind Uke to the perpendicular line. Extending and sinking should then cause Uke to fall right back on his seat, not giving him the chance to roll away. Uke might open his eyes wide on the fall and curse so be prepared to grin. :)

If Uke is in motion and is rotating towards you for a strike, for example, then keep in mind the changing perpendicular line between his feet on the extension.