Sumi-otoshi (corner drop) is a hand technique from the fifth group of the gokyo. Tori steps in just as uke puts his foot down, then tips him toward his rear corner with both hands. No leg contact at all. It is close to pure kuzushi.
A judo throw with no fulcrum
Most throws give tori some kind of lever: a hip, a blocking leg, a shoulder. Sumi-otoshi has none. It belongs to the te-waza (hand techniques) of nage-waza, next to uki-otoshi, its mirror image.
The gokyo puts it in the fifth group, which matches its difficulty. Without precise kuzushi, the throw does not exist. No body type and no amount of strength makes up for a missed off-balance.
Timing: catch the landing heel
The key moment is when uke steps forward with his right foot and his heel touches the mat, before his weight rolls onto the ball of the foot. For that split second his center of gravity sits right above his right heel. A small push in the right direction is enough.
Arrive too early and his foot is still in the air, so he simply puts it down farther away. Arrive too late and his weight has already moved forward.
How to do sumi-otoshi (right-handed)
Start from a standard grip: hikite (pulling hand) on the right sleeve, tsurite (lifting hand) on the left lapel.
Uke steps forward with his right foot. You step your left foot to the outside of his right foot, almost against his heel. Your body closes the distance.
Both hands work as one. The tsurite pushes toward his right rear corner and down, as if driving him into the mat behind his heel. The hikite pulls the sleeve down in the same direction, along an arc. Your upper body leans forward to follow through.
Uke tips backward on a diagonal. He cannot step back with his right foot because all his weight is on it.
Common mistakes
- Pushing straight back. Uke steps back with his left foot and recovers.
- Pushing with one arm. There is no rotation.
- Staying too far away. Without your left foot against his heel, he has room to catch his balance.
- Waiting for uke to stand still. Sumi-otoshi happens on a step, never against a planted opponent.
Sumi-otoshi or ko-soto-gari?
Beginners mix them up because uke falls the same way. In ko-soto-gari, tori's foot reaps uke's heel. In sumi-otoshi, nothing touches the leg. The direction of the push pins the foot under uke's own body weight.
We like to teach both in the same session. When ko-soto-gari gets blocked because uke feels the foot coming, sumi-otoshi is still there, since there is nothing to feel.
Does sumi-otoshi work in competition?
Rarely as a direct attack. High-level opponents seldom move with big, regular steps. You see it more in combinations. After a forward attack, uke straightens up and settles back on his heels, and that is the window. A blocked tai-otoshi, for example, often triggers exactly that reaction.
It suits light, quick judoka better than powerful ones who look for contact. Against a taller opponent it works better than people expect. A high center of gravity makes him sensitive to a push toward the rear.
Drills for sumi-otoshi
Start walking forward, with uke moving in slow ayumi-ashi (normal walking steps). Tori follows the rhythm and, each time the right foot lands, pushes lightly toward the rear corner without throwing. Uke should feel the off-balance. Then, on a thick mat, uke lets himself fall into a back breakfall.
Real progress comes when uke varies the rhythm of his steps. Tori then learns to see the heel land. That reading of footwork will help every rear throw in your judo.