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Summery

This is a Judo throw that is classified as a hand throwing technique.

Technique

Step with your left foot (or right foot) beside opponent's right foot (or left foot). Using your body movement and both hands put opponent off balance to his right backward (or left backward). Then, push opponent up and throw him down.

Difference

Sumiotoshi and Ukiotoshi are mentioned in Ukiotoshi section as Kukinage. Both use only hands to throw down. In Sumiotoshi you take opponent's body off balance to his right backward (opponent's right heel) and throw down in the direction of opponent's right heel. In Ukiotoshi you take opponent's body off balance to his right forward (opponent's right toe) and pull down or push down to throw in the direction of opponent's right toe.

It is easy to understand the difference between these two techniques since the direction of putting off balance and throwing is opposite.