Tomoe nage - circle (sacrifice) throw
Film of the execution of this technique:
mamae no kuzushi
Tori puts down his linkerbeen between the feet of uke and puts his rechtervoet on the button of the link of uke. Tori lets himself fall now backwards as a result of which uke is thrown.
During the throw his rechterbeen can tori extend. This is however not necessary: the rechterbeen is rather a conductance leg then a leg force uke to falls.