01 / AT A GLANCE
Sumi-otoshi: the defining action
Sumi-otoshi is a corner drop produced through hand control and body movement toward uke’s rear corner. The defining task is to move the shoulder line outside a recoverable base without making a reap, hip load or sacrifice the principal mechanism.
Name and scope: Sumi-otoshi (隅落), commonly rendered as corner drop, belongs to Te-waza. Searches for “sumi otoshi” and the hyphenated spelling refer to the same official technique here. An informal nickname should be checked against the actual action before being treated as a separate technique.
Position convention: This guide directs uke toward uke’s right-rear corner. Tori steps into an outside relationship near uke’s right foot and coordinates the hands with a body shift. Left and right describe the partner’s own sides rather than the viewer’s screen. Tori means the person performing the technique and uke the receiving partner. When reviewing a mirrored camera image, identify each person’s own sides first. Reverse the whole relationship for a left-sided lesson rather than changing one limb while preserving incompatible directions elsewhere.
The intended reader can already practise under supervision and wants to connect demonstration, diagnosis and decision-making. For sumi-otoshi, the central question is: move the shoulder line into the rear corner that the feet cannot immediately recover. Beginners can study the shape with a coach; applying it against variable resistance requires the additional recognition and control work below. The article does not assign a universal belt level or promise that one body type will succeed automatically.
02 / WATCH THE TECHNIQUE
Official demonstration and a second viewing reference
Open this video on YouTube if the player is unavailable.
Open this video on YouTube if the player is unavailable.
Follow the outside step and the direction of uke’s shoulder line. Compare the hand-led drop with demonstrations of sumi-gaeshi so that the shared name does not obscure the different mechanism.
Official reference: Kodokan. Second demonstration: Efficient Judo. Open the publisher links if either embedded player is unavailable.
A practical viewing question is: “Which recovery step am I removing through angle and shoulder control, rather than through a hidden trip?” Compare that question across the official and second reference. Differences in speed, partner stance or grip route may explain different appearances. Do not combine isolated details from incompatible versions into one repetition. No timestamps or claims about unseen scoring sequences are supplied here.
03 / WHEN TO USE IT
Recognise an opening and recognise its absence
A usable starting relationship
Uke’s posture becomes upright or moves backward while the near shoulder remains connected. Tori can enter the outside angle without reaching over a stable, widely separated stance.
In the selected right-rear-corner form, tori’s left foot steps outside uke’s right foot while the hands direct the shoulder line diagonally backward. Naming that supporting step makes the entry easier to compare than the vague instruction to move outside. The step should carry tori’s torso into the action without trapping uke’s leg. If the arms extend before the support arrives, uke can often recover with a comfortable backward step.
When the same shape is not an opening
Uke’s trunk remains forward, the shoulders can turn freely or the outside approach is blocked. Pushing straight backward against a balanced stance does not create the missing corner.
A square stance with both shoulders mobile can absorb a straight backward shove. Test the difference by asking uke to recover with one ordinary step during a slow preparation. Tori first tries the habitual line, then refines the diagonal corner with the coach. Keep force modest and watch the recovery route. If a concealed heel block is required for the second attempt, the hand-led corner action has not yet been isolated.
Movement to invite or read
Let uke move between forward pressure and upright recovery. Tori studies the moment the shoulder line returns toward the rear corner while preserving a short, balanced outside step. In an opposite-lead or unfamiliar grip arrangement, have the coach map the relevant limbs again. The fixed convention in this article provides a reference for comparison; it does not guarantee that the same approach distance survives every stance.
04 / HOW IT WORKS
Connect the grips, support and finishing action
Hands and upper-body connection
The hands contain the near shoulder and direct the upper body toward the right-rear corner. They act with the moving torso rather than straightening the elbows into an isolated shove.
Feet, hips and available support
Step into a stable outside angle near uke’s right foot while preserving room for the fall. The support stance carries the body shift; avoid placing a foot where it accidentally traps uke’s knee and changes the intended action.
Complete the action under control
Continue the corner direction as uke’s base can no longer move beneath the shoulder line. Retain guidance during the drop and keep enough posture to accompany the landing. A concealed trip may produce a fall, but it does not demonstrate the hand-led mechanism being studied.
Study the relationship beneath the visible shape
A rear corner is not simply a point behind the opponent. It is a direction in which the shoulder line can leave the base faster than the feet can reorganise beneath it. If tori pushes directly backward, uke may have an easy recovery step. If the near shoulder is allowed to turn, uke may recover sideways. The outside approach and hand connection need to close the particular recovery route available in that stance. This is why a small change of angle can matter more than a large increase in force.
Rehearse the body shift with the attacking feet kept clear of uke’s legs. This makes it easier to see whether the hands and torso genuinely influence the balance. If the exercise succeeds only after tori adds an unnoticed heel block, the practice has supplied evidence of a different mechanism. That is useful information, but it should be named accurately rather than concealed inside the sumi-otoshi label.
05 / KEY POINTS
Four cues with observable checks
Keep the defining mechanism visible
Move the shoulder line into the rear corner that the feet cannot immediately recover. Ask the observer to describe that action before commenting on power. If a repetition succeeds through a different mechanism, record what actually happened. A fall or escape can be useful without proving that the intended sumi-otoshi relationship improved.
Verify the position before adding commitment
A slow preparation should reveal a diagonal rearward shoulder change rather than a straight push into both heels. Tori should remain balanced without needing to hook a leg. Use this as a brief checkpoint in cooperative practice, then remove the pause as coordination improves. The checkpoint is not a recommendation to freeze during a live exchange; it is a way to identify the relationship that must survive movement.
Preserve the correct stopping decision
Use a coach-arranged unavailable position to check your decision before adding resistance to sumi-otoshi. The precise release or reception boundary is described in the defence section below. Otherwise, a partner who always supplies the ideal opening can teach commitment without teaching selection. A correct reset belongs in the practice record alongside a controlled completion.
Make the result lead to a next position
Tori may remain standing beside the near arm as uke descends. Guide that arm without pulling it behind the shoulder, then lower into a stable position beside the torso. The observer should describe the actual ending, not the intended ending. That description determines whether the next task belongs to finishing, stabilising on top or recovering underneath.
06 / PROBLEMS & ADJUSTMENTS
Diagnose the earliest cause before changing force
Uke takes one comfortable backward step and restores the original stance.
The force may be directed straight backward into an available recovery step. The sleeve-side shoulder may be free to rotate away before the body shift arrives. These are competing explanations to investigate, not a diagnosis made from the result alone. The next repetition should reveal which relationship fails first.
Test: Rehearse the outside step without finishing and let uke recover naturally. Observe which foot moves and which shoulder opens. Change only the angle or shoulder containment, then compare the size of the recovery step. Adjustment: Refine the rear-corner angle and keep the near shoulder connected during the outside approach. Keep the other conditions as similar as practical for the comparison. An improvement in the relevant connection is more informative than one accidental completion after several unrelated changes.
Throw works only with a foot behind the heel
If a partner can be dropped only after tori adds a foot behind the heel, examine whether the exercise has become a different technique. Removing that extra contact is a useful diagnostic, not a demand to force the same finish harder. For sumi-otoshi, partner feedback should identify where the action was felt and when it changed. Combine that report with the observer’s view; an outside camera and an inside contact sensation provide different pieces of evidence.
Read the direction of uke’s recovery step
Use recovery steps as diagnostic feedback. Let uke take one step when the corner pressure begins, without deliberately resisting or falling. The observer notes its direction and the shoulder movement that permitted it. A straight backward step may indicate that the intended diagonal was missing. A turn away may indicate that the sleeve-side shoulder escaped. A small step that still fails to recover the trunk may indicate that the corner was available but the finishing connection needs refinement.
Repeat the same starting stance when comparing corrections. If uke changes foot width and tori changes the grip at the same time, the next result is hard to interpret. First adjust the approach angle; then, if necessary, adjust the shoulder containment. Once the relationship is understood, deliberately vary the stance so the learner can adapt rather than memorise one fixed arrangement.
07 / SETUPS & COMBINATIONS
Make the next action depend on a response
First route: starting position, response and continuation
Invite a forward response with a controlled uki-otoshi preparation. If uke restores posture by bringing the trunk backward while the sleeve remains connected, step into the outside angle for sumi-otoshi. If the response stays forward, continue the original movement or reset.
In the uki-otoshi preparation, tori offers a credible front-corner threat without committing to a blind downward pull. Uke chooses to keep following or recover the shoulders backward. Tori changes to sumi-otoshi only for the backward recovery while the grip remains close. The observer checks the left supporting step outside uke’s right foot. This makes the change depend on a new rear corner instead of an arbitrary reversal of arm force.
Second route: recovery or change of direction
A ko-uchi-gari threat may make uke withdraw the near foot and rise. Once tori has a stable facing stance, use the resulting rear corner if the shoulders remain close. If the withdrawal opens a large gap, regain grips rather than pushing across empty space.
After a ko-uchi threat, uke may withdraw the foot but keep the trunk forward, or may rise and recover backward. Only the second response supports the described rear-corner continuation. Tori brings the left support to the outside angle after the recovery, keeping the near shoulder close. A large backward retreat can remove the distance entirely. End that repetition in facing posture rather than pushing through extended arms to satisfy the sequence.
08 / DEFENCES & COUNTERS
Separate prevention, recovery and a counter opportunity
Uke can maintain a stepping base under the shoulder line and turn the whole body before the rear corner closes. Posting a straight arm after the drop has begun is not a safe replacement for earlier footwork.
Stop boundary: Recover the approach if uke’s shoulder has escaped, the rear corner is no longer available or tori would need an unintended knee block to force the finish. The receiving partner must retain an agreed ukemi response when the original attack has succeeded. Do not replace reception with a desperate straight-arm post or a joint-twisting rescue.
Uke prevents the corner drop by moving the shoulder line and base together before the diagonal is closed. Give uke either a backward step or a turn away, then observe which shoulder motion allows it. Tori uses that information to refine angle and containment. After the corner is already lost, uke receives the fall rather than reaching a straight arm behind the body. Prevention and late reception belong to different phases of the drill.
09 / GROUND TRANSITIONS
Read the position after the main action
A back landing can permit a side hold once chest contact and knee placement are established. A side landing may require following the shoulder rather than chasing the hips; pause the transition if the near arm becomes trapped underneath.
If uke lands on the side, the near arm may be beneath the torso rather than available for a scarf hold. Avoid pulling that arm backward while reaching over the shoulders. First stabilise alongside, let the arm move through a comfortable route and choose the hold from the actual position. If uke rolls to the knees, keep a balanced top angle. The original standing corner control should evolve into shoulder control appropriate to the ground.
A completed throw and an established hold are separate outcomes. A controlled landing can still require leg clearance or shoulder repositioning before useful top control exists. Compare the actual sumi-otoshi ending with the planned one, and practise the common arrival independently if it repeatedly becomes the weak part of the sequence.
10 / PRACTICE PROGRESSION
Progress from a clear shape to a real choice
Stage one: make the reference repeatable
Use the stated sumi-otoshi convention with a cooperative partner. Begin slowly enough to identify the grip and support roles, and stop before completing an action that has lost its defining connection. Progress when both partners and the observer can describe the same relationship without guessing. Repetition count alone does not establish readiness.
Stage two: introduce the movement cue
Revisit the specific moving relationship described under “When to use it” for sumi-otoshi. First keep its direction predictable, then vary its timing while preserving the same grips and side convention. Keep resistance modest while the cue changes. If the reference shape disappears on every moving attempt, reduce the step or escape amplitude and preserve the correct direction rather than forcing a finish.
Stage three: require a decision
Uke sometimes recovers backward and sometimes circles away. Tori chooses the corner drop only for a contained backward recovery and uses a facing reset for the circle. A useful round includes a correct continuation and a correct decision not to continue. Record both. When these choices remain clear, increase unpredictability before increasing force, with the coach deciding what the pair can control.
Stage four: constrain the exchange, then broaden it
A practical movement drill alternates forward pressure with an upright backward recovery. Tori does not attack the first movement automatically. The task is to recognise the recovery that brings the shoulders into the rear-corner relationship while the grip remains close. Add a circling response later so that tori must decline a corner that has disappeared.
In review, distinguish a controlled corner drop from a partner falling because the exercise was agreed in advance. Uke should provide ordinary balance and an honest recovery step within the drill’s limits. The aim is not maximal resistance, but credible information. A useful log records which recovery route was closed and whether tori remained balanced enough to guide the landing. Those observations explain the result more clearly than a general statement that the hands felt strong.
11 / COMPETITION EXAMPLE
A named official replay selection to study
Verified selection: Eteri LIPARTELIANI vs Rafaela SILVA — World Judo Championships - Doha 2023 Mixed Teams. The IJF technique library page includes this contest in its Sumi-otoshi technique-tagged replay data. The listing verifies the named pairing, event and technique tag. The listing credits the tagged action to Rafaela Silva. It does not by itself establish the final score, a precise timestamp or a complete tactical account.
Use the selection to investigate one question: “Which recovery step am I removing through angle and shoulder control, rather than through a hidden trip?” Before the tagged action, identify the grips and movement that made the situation possible. During the action, compare the defining connection with the official demonstration. Afterward, identify recovery and position. If the player or angle does not show one of those phases, leave that part of the observation blank rather than inferring it from the tag.
A useful competition note for sumi-otoshi separates three things: what the official listing states, what you can actually see in playback and what you propose to test in practice. This article confirms the first and supplies prompts for the other two. It does not present an unviewed sequence as a frame-by-frame analysis, nor treat historical footage as certification under current event rules.
12 / VARIATIONS & COMPARISONS
Keep neighbouring techniques and variants distinct
Uki-otoshi addresses the front corner. Sumi-gaeshi is a sacrifice throw with a different leg-and-body relationship despite sharing the word corner. Ko-soto-gari can attack a nearby rearward opportunity, but its reap is mechanically distinct from this hand technique.
Uki-otoshi supplies the front-corner comparison, whereas sumi-gaeshi uses a backward body sacrifice and leg assistance. Ko-soto-gari removes a rearward support through a reap. Sumi-otoshi should remain identifiable when the intentional leg action is absent: the outside step and coordinated hand-and-body direction create the drop. A similar rearward landing does not make those mechanisms interchangeable.
13 / YOUR NEXT PRACTICE
One task, one observation and one next decision
Task: Make eight outside-angle entries and identify whether the available recovery step is backward, sideways or already closed.
Record: Record the shoulder angle, the recovering foot and whether a leg block was added unintentionally. Use the practice record template or the practice tools described in Judo AI. Include the starting stance, partner response and the single adjustment tested, so the observation remains interpretable at the next session.
Illustrative example — not measured user data: In a sample set, five attempts allowed a straight backward step and three reached a true diagonal corner. Changing the approach angle reduced the comfortable recovery step in the next set without increasing arm force.
Coach question: “Which recovery step am I removing through angle and shoulder control, rather than through a hidden trip?” Bring one clear success and one clear failure if recording is permitted. For sumi-otoshi, choose the next drill from the earliest difference between them. Keep an adjustment that improves the intended connection across several comparable attempts; revise it when the predicted change does not appear. The purpose of the record is a better next decision, not a decorative count of repetitions.
14 / SOURCES & REVIEW
Sources, authorship and review
Kodokan official technique names establish the name and category. The IJF Sumi-otoshi definition and video library and linked Kodokan demonstration are the primary technical references. The second video above is credited separately. The official replay listing in section 11 verifies the named contest and technique tag, not an unviewed score or every coaching proposal here.
The Kodokan definitions (October 2022) are an additional reference for the technical distinctions discussed above. Side conventions follow the explicitly selected form, not a mixture of mirrored examples.
By Judo AI · Editorial review: October 9, 2026. Definitions, source identity, article consistency and links have been checked. Practice tasks and diagnostic questions are editorial proposals to discuss with your coach, not a validated training protocol. Named technical-coach approval is still pending. Video identities were verified; complete playback and every contest detail have not been independently analysed.
Rules and scope: this is a supervised judo study guide, not a current refereeing manual. Historical footage does not establish current rule permissions. Ask your coach to check the applicable age group and event rules before using grip variations or submissions in shiai; this draft does not certify their legality. Stop a practice action when your partner taps, asks to stop or reports pain.