01 / AT A GLANCE
An elbow lock held inside a leg triangle
Ude-hishigi-sankaku-gatame, usually called sankaku-gatame, is the triangular arm lock. The Kodokan’s official list of 100 techniques places it ninth of the ten kansetsu-waza (joint locks) in katame-waza. The IJF technique library labels it “triangular armlock” and defines it as follows: “A lock. From your opponent’s front, rear, or side, wrap your right leg over his shoulder and across his neck, and your left leg under his right armpit, hooking one of your feet under the other leg in a triangular formation. At the same time, use one or both hands to extend and control his elbow joint.”
That definition sets three things: the triangle (one leg over a shoulder and across the neck, the other under the far armpit, one foot hooked under the other leg), the target (the elbow joint) and the tool that finishes (one or both hands extending the elbow). Sankaku means triangle and refers to the shape of tori’s legs. The same leg shape also appears in sankaku-jime, the triangle strangle in shime-waza. The difference is the target: the jime acts on the neck, the gatame acts on the elbow. Treat them as separate techniques with separate agreements in practice.
Names you will meet: sankaku-gatame, ude-hishigi-sankaku-gatame, “triangular armlock” (IJF) and “triangle armlock”. Coaches also say “sankaku” for the whole family of triangle controls, which is why the target must be named every time.
Who this guide is for: judoka who already do supervised ne-waza, have been shown a turnover against an opponent on all fours and know at least one other arm lock. The section 4 safety box applies to every drill on this page.
02 / WATCH THE TECHNIQUE
The official form from all fours, then a coaching variation
Open this video on YouTube if the player is unavailable.
This is the official Kodokan–IJF Academy demonstration. We checked its identity and publisher with YouTube’s oEmbed record and viewed sampled frames during playback, but did not analyse it frame by frame. At the level those frames show: after the title card, uke is on all fours and tori kneels at uke’s head, over uke’s back; tori then rolls to the side and back, and in the locking frames uke lies on the back beside tori, with tori’s legs around uke’s head and one arm, and that arm stretched along tori’s body while tori’s hands hold the wrist near tori’s chest. The action is repeated and shown from other camera angles. Watch with these questions:
- Which leg goes in first, and where does it enter: over the shoulder, or under the armpit?
- When do the feet lock: before tori starts to roll, or during it?
- What turns uke over: tori’s roll, the legs, a grip on uke’s body, or a combination?
- Where does the trapped arm lie as the hands extend it, and what part of tori’s body is under the elbow?
Open this video on YouTube if the player is unavailable.
We have verified only this clip’s title, publisher, date and length, and read the publisher’s description, which presents it as a way to use triangle control with the legs to pressure an extended, straight arm. We have not analysed the action, so this page does not describe it. Watch with one question: is the triangle complete before any pressure reaches the elbow, or does the arm pressure arrive while the legs are still settling? The publisher describes the armlock as quick; in your practice the extension stays slow regardless of the entry.
03 / WHEN TO APPLY IT
The opening is a gap between uke’s arm and head
Sankaku-gatame is most often studied against an opponent on all fours or flat on the front, because that position offers the gap the first leg needs. Three questions decide whether the opening exists: Can your leg go over uke’s shoulder and across the neck while uke’s arm stays inside? Can your other leg reach under the far armpit? Can your feet lock before uke flattens out or stands up?
Uke turtles after a failed throw or turnover
When uke goes to all fours to avoid a hold, elbows and knees are often slightly apart, and the shoulders are in front of you if you are at the head. A gap between uke’s left arm and the side of the head is where your right leg can travel over the shoulder.
Uke reaches up while defending from all fours
An uke on all fours who reaches for your leg, belt or sleeve lifts an arm away from the body. That arm is easier to enclose with the head, and later easier to pull out straight.
When the lock is not available
If uke is flat with both elbows clamped to the ribs and the head tucked, there is no gap for the leg. If uke is already standing up, the triangle cannot be set safely. If uke has the far arm posted wide, your left leg will struggle to reach the armpit. In those cases keep top pressure, or work for a different turnover. If uke is on the back, a straight arm between your thighs suggests juji-gatame instead, and a bent arm suggests ude-garami.
04 / HOW IT WORKS
Triangle, turnover, isolation, extension
The lock has four phases. The triangle encloses uke’s head and one arm. The turnover brings uke onto the back. Isolation frees the enclosed arm from any clasp and draws it out along tori’s body. Extension straightens the elbow with the hands. Each phase needs the previous one to be finished.
What is definitional and what is not: the IJF definition fixes the leg routes (right leg over the shoulder and across the neck, left leg under the right armpit), the foot hooked under the other leg, the start from front, rear or side, and the finish with one or both hands on the elbow. The order of the legs, the roll, grips on the belt or jacket, and where the elbow rests are commonly taught details for confirmation with your coach.
Right leg over the left shoulder
From uke’s head, your right leg travels over uke’s left shoulder so the thigh lies across the back of uke’s neck, leaving uke’s left arm inside, next to the head. The leg rests on the shoulder line; it does not press down on the cervical spine. Check: uke tries to pull the left arm out of the triangle. If it slides free easily, the leg is too far down the back, behind the arm rather than over the shoulder.
Left leg under the right armpit
Your left leg goes under uke’s right armpit, from the front, so uke’s right arm is outside the triangle. Check: can uke drop the right elbow to the mat and block the leg? If yes, the leg entered too late or too low; the armpit gap closes quickly.
Feet hooked into the triangle
One foot hooks under the other leg, as the IJF wording says; many coaches teach the right foot hooked behind the left knee. The triangle holds the shoulder and neck region so uke cannot withdraw the head or the arm. Check: the hook stays closed when uke shifts the hips. If the foot keeps slipping, the triangle is too large, usually because the first leg was too low.
Turnover without cranking the head
With the triangle locked, you roll to your side and back so uke follows onto the back beside you. The roll should move uke’s whole upper body; the head simply travels with the shoulders inside the triangle. Check: the coach watches uke’s neck during the roll. Any sharp bending of the head toward the chest or to the side means stop: the body is not turning with the legs.
Arm isolated along your body
Once uke is on the back, both hands take uke’s left wrist and draw the arm out of any clasp along your torso, so the upper arm stays pinned by the triangle and the forearm is in your hands. Check: before any extension, can uke bend the elbow back toward the face? If yes, the triangle is not holding the upper arm close to the head.
Slow extension with the hands
With the upper arm held and the wrist in your hands near your chest, the elbow is extended gradually, with the elbow joint against your body as the coach places it. The IJF wording is “use one or both hands to extend and control his elbow joint”. Check: uke reports where the first sensation is at minimal extension. The answer must be the elbow; if uke reports the neck or shoulder, stop and rebuild.
Neck pressure is not the target here
Because the triangle surrounds the neck, squeezing the legs can compress it. In sankaku-gatame the legs hold; they do not squeeze. If uke taps or says “stop” for any reason, including neck pressure, you release in full. Agree in advance that the drill is an armlock drill, so both partners know the hands, not the legs, are the finishing tool.
Release is part of the mechanics
On a tap, a spoken “stop” or any sign of pain, let the arm bend first, then open the hands, then unhook the feet, then open the legs and let uke’s head out. Unhooking the feet while the elbow is still extended can let uke move suddenly with the arm still loaded. Rehearse the order on every repetition.
05 / KEY POINTS
Four cues about the order of completion
Section 4 builds each phase in place. These cues check whether each phase is finished before the next begins during a live entry. Use one cue per set.
Hook before roll
The feet are locked before you start the turnover. Check: the observer watches only your feet and your shoulders and calls which moved first.
Body turns, head follows
Uke’s shoulders and hips turn together during the roll. Check: the coach watches uke’s head and says whether it led, lagged or travelled with the shoulders.
Wrist before extension
Both hands secure uke’s left wrist and draw the arm along your body before any straightening. Check: is there a pause between “wrist secured” and “extension starts”? No pause usually means the arm was pulled straight in one movement.
Release in the trained order
Arm bends, hands open, feet unhook, legs open. Check: on the coach’s call, the feet stay hooked until the arm is bent.
If a cue fails twice, return to the static triangle on all fours (stage 1 in section 10). Most extension problems in this lock start as a loose triangle.
06 / PROBLEMS & ADJUSTMENTS
Why the triangle slips or the arm stays hidden
Diagnose from the first thing that went wrong; each entry is a hypothesis to test with your coach.
“My feet won’t lock” or “the triangle keeps opening.”
Possible causes: your right leg went in low on uke’s back instead of over the shoulder, making the loop too big; your left leg entered beside the armpit rather than under it; or uke widened the shoulders as you hooked.
Tell them apart: freeze at the hook. If your right thigh is behind uke’s arm, it is the first leg; if your left shin sits on uke’s upper arm, it is the second leg; if both are placed but uke’s shoulders spread, it is uke’s reaction.
Adjustment: re-enter with the right thigh on the shoulder line, close to the neck, and the left leg fully under the armpit before hooking. Assess: five static hooks against the same slow shoulder spread; count triangles that stay closed.
“Uke won’t turn over.”
Possible causes: uke posts the free (right) hand or a knee wide on the far side; you rolled before the feet were locked; or you tried to turn uke with the head rather than the shoulders.
Tell them apart: watch the far side. A wide right hand or knee is a post; a triangle that opened during the roll is timing; an uke who turns only at the neck is the wrong lever, and a reason to stop.
Adjustment: lock first, then roll toward the side where uke has no post. If uke keeps posting, keep top control and set up again; never force the roll through the neck. Assess: uke gives the same post on five repetitions; count turnovers completed with the head moving with the shoulders.
“Uke is on the back but I can’t get the arm out.”
Possible causes: uke has clasped hands, gripped the own jacket or belt, or pulled the left forearm across the face; your hands reached the forearm instead of the wrist; or the triangle has loosened so the upper arm can move.
Tell them apart: look at what is holding. A clasp needs a separation method; a forearm grip is a hand placement issue; a moving upper arm is a triangle issue.
Adjustment: tighten the triangle first, then work the separation your coach teaches, slowly. Never yank a clasp: when it breaks, the arm can travel to full extension at once. A broken clasp means pause, then extend slowly. Assess: record whether the arm came out under control and whether uke ever reached end range without warning.
“Uke taps for the neck, not the elbow.”
Possible causes: you squeezed the legs while trying to extend; the right thigh lies across the front of the throat rather than the side of the neck and shoulder; or uke’s chin is trapped.
Tell them apart: ask uke at zero arm pressure whether the neck is uncomfortable. If yes, it is leg position; if it starts only when you extend, you are squeezing.
Adjustment: release, then rebuild with the leg on the shoulder line, and keep the legs at holding tension while the hands work. Assess: on every repetition of the next set, uke reports neck comfort before the extension and the first sensation location during it.
“The pressure is in the shoulder.”
Possible causes: the arm is being pulled across uke’s body rather than along yours; the elbow is not resting on your body, so there is no fulcrum at the joint; or uke has rotated the arm.
Tell them apart: the coach compares the line of uke’s forearm with your torso and checks where the elbow rests.
Adjustment: stop and redirect the wrist along your torso with the elbow set where your coach places it. Never pull harder to find the elbow. Assess: uke names the sensation location on each repetition; only the elbow continues.
07 / ENTRIES & COMBINATIONS
Read the arm, and know when to stay in control
These are editorial practice patterns for supervised training, not descriptions of the linked videos. Each names where the attempt is abandoned.
READ THE GAP
Uke on all fours: triangle, other turnover, or keep pressure
Start: uke on all fours, you at the head. Partner response, three cases: (a) a gap between uke’s left arm and head, with the right armpit open; (b) uke clamps both elbows and tucks the head; (c) uke starts to rise onto the feet. Next action: (a) is this guide’s opening: right leg over the shoulder, left leg under the armpit, hook, then roll. (b) offers no leg route: keep chest pressure on uke’s back and wait or use a turnover your coach teaches. (c) means stop the attempt and follow the agreed positional rule. Stop or reset: if your feet are not hooked when uke starts to rise, abandon the legs and keep upper-body control.
TRIANGLE, THEN TARGET
Triangle complete → armlock or strangle by agreement
Start: uke on the back beside you inside the triangle. Partner response: uke protects the left arm with a clasp. Next action: keep the triangle at holding tension and work the arm slowly. Your coach may also teach sankaku-jime from this shape; only switch target if the round’s agreement allows strangles and your partner knows it. Stop or reset: if you are squeezing the legs to make the arm move, you are mixing two techniques; stop and rebuild.
AFTER THE LOCK FAILS
Arm hidden → transfer to a hold-down
Start: uke on the back, triangle on, arm protected. Partner response: uke keeps the clasp and tries to sit toward you. Next action: come up onto your hip, put your chest weight on uke’s upper body, and move to a hold your coach has taught from that position, for example toward kuzure-kami-shiho-gatame or yoko-shiho-gatame. Open the legs only once your upper body has control. Stop or reset: if uke has turned onto the knees again, return to the start case.
For each attempt, note two facts beyond the result: whether the hook was set before the roll, and whether you kept control when you abandoned. Those two usually explain the finishes.
08 / DEFENCES & ESCAPES
Close the gap, stop the roll, keep the elbow bent
Every defence removes one phase from section 4: the triangle, the turnover, the isolation or the extension. The earlier the phase, the safer the defence.
Prevention: no gap between arm and head
On all fours, keeping the elbows close to the knees and the head tucked between the arms leaves no route for tori’s leg over the shoulder with the arm inside.
Early defence: before the feet lock
While only one leg is in, uke can pull the enclosed arm out of the gap or drop the far elbow to block the armpit route. Once the feet are hooked, these become harder and the defence moves to the turnover.
Escape: stop the turnover, then protect the arm
Posting the free hand and a knee wide on the far side can stop the roll. If uke is turned, keeping the trapped elbow bent and the hands connected delays the extension while uke works to sit up or face tori. Defences that pull or twist the head out of the triangle are not safe practice.
Counter exposure for tori
Tori is on the side or back with both legs committed. If uke escapes the triangle, uke may come out on top. That is why section 7 transfers to a hold before the legs open.
09 / TRANSITIONS FROM THE TRIANGLE
What the triangle gives you when the arm doesn’t come
Sankaku-gatame is reached through a turnover, so it sits between top control on an uke on all fours and a hold-down on an uke on the back. This study map shows where each phase can lead.
| Phase reached | What uke does | Next decision |
|---|---|---|
| One leg in, no hook | Pulls the arm out or flattens | Withdraw the leg and keep chest pressure on uke’s back |
| Triangle hooked, uke still on all fours | Posts wide to stop the roll | Hold the triangle and re-time the roll, or release and reset |
| Uke turned, arm hidden | Clasps or grips the own judogi | Separate slowly, or transfer to a hold-down |
| Uke turned, arm isolated | Tries to bend the elbow | Slow extension with the hands, tap and release |
Into and out of holds
Uke often goes to all fours to escape a hold or a throw, and the triangle turnover is one way to bring uke back onto the back. When the lock does not come, the turnover still gives you a position near a hold: your chest is close to uke’s upper body and uke’s head and one arm are controlled. The trade is that your legs are committed; transfer to a hold your coach has taught before you open them.
Relationship with the strangle
The triangle that holds uke for sankaku-gatame is the same shape used in sankaku-jime. In this guide it is a control, not a weapon. If your coach teaches both, practise them in separate blocks with separate tap agreements so neither partner is surprised by a change of target. For broader ne-waza session design, see the ne-waza drills guide.
10 / PRACTICE PROGRESSION
From a static triangle to positional rounds against all fours
Advance only when the criterion is met with the coach watching; progression is gated by control, neck safety and release.
Static triangle on all fours
Uke on all fours, still. You build the triangle and hook the feet, then stop. Uke tests one arm pull and one shoulder spread; the coach checks the leg against the side of the neck. Criterion: the triangle stays closed, uke’s arm stays inside, and uke reports no neck pressure.
Turnover only
From the hooked triangle, roll uke onto the back and stop, with no arm work. Criterion: on every repetition the coach confirms that uke’s head travelled with the shoulders, and uke reports no neck discomfort.
Isolation and slow extension
From the turned position, secure the wrist, draw the arm along your body and extend in stages; uke taps at the first clear elbow sensation and you run the release order. Criterion: every tap produces immediate release in the trained order, and uke always reports the elbow.
Positional rounds with one defence
Short rounds: uke starts on all fours and tries to stand or flatten; you may keep top pressure, attempt the triangle, or transfer to a hold. A tap, uke standing, or loss of control ends the round. Criterion: the coach judges that your attempts match the section 7 read and that no turnover was forced through the neck.
Free ne-waza randori with this lock comes after stage 4, once the coach judges the release habit reliable and confirms eligibility.
11 / COMPETITION REPLAYS
Official replay leads, and their limits
We checked these IJF technique-library pages on October 14, 2026. Each is a replay lead: the contest appears under the sankaku-gatame tag; what happened in it is not verified, and we have not watched the footage.
Emma Reid (GBR): six tagged contests
The IJF technique page lists Emma Reid as the athlete most associated with the tag, and the IJF page headed “Sankaku-gatame by REID Emma” lists six contests, including two at the European Senior Championships 2026 (against Anna Kazakova and against Metka Lobnik) and one at the Grand Prix Portugal 2024 against Karol Gimenes.
Munkhbat vs Ungureanu, World Championships 2019
The IJF page headed “Sankaku-gatame on World Championships Senior 2019” lists a contest between Urantsetseg Munkhbat and Monica Ungureanu. The event page does not state which athlete performed the tagged action.
Verified: page titles, events, pairings and tags. Not verified: whether a score resulted, the time in the contest, the preceding position and any tactics.
Viewing questions to take to the replays
- Origin: was the opponent on all fours, flat, or coming out of a throw? From the front, side or rear?
- Triangle: which leg entered first, and did the feet hook before the turnover?
- Turnover: did the opponent post, and how did the athlete deal with it?
- Arm: was the arm already free, or did it have to be separated from a clasp?
- Ending: how quickly did the referee stop the action and the athlete release?
Record only what the camera shows; mark the rest “not visible”. Elite footage reflects that event’s rules, not your division’s.
12 / VARIATIONS & COMPARISONS
Sankaku-gatame among related techniques
The Kodokan list separates techniques by what they act on. The triangle shape alone does not decide the name.
| Technique | Group | What does the work |
|---|---|---|
| Ude-hishigi-sankaku-gatame | Kansetsu-waza | Leg triangle holds; one or both hands extend the elbow (IJF) |
| Sankaku-jime | Shime-waza | The leg triangle acts on the neck |
| Ude-hishigi-juji-gatame | Kansetsu-waza | Thighs trap the upper arm, hands hold the wrist (IJF) |
| Ude-hishigi-hiza-gatame | Kansetsu-waza | Tori’s knee presses the elbow (IJF) |
| Ude-hishigi-ude-gatame | Kansetsu-waza | Tori’s hands and arms against the elbow |
| Ude-garami | Kansetsu-waza | Both arms entangle and twist a bent arm |
Rows without “(IJF)” summarise what the names and grouping indicate; study each from its own guide and official demonstration.
Variations within sankaku-gatame
Starting side: the IJF definition allows front, rear or side; this guide uses the front because the official clip starts there. Rear and side entries change which leg moves first and need coaching. Hand finish: one or both hands, as the definition allows; the two-handed wrist hold is the easier one to control slowly. Bent-arm or other-arm finishes from the triangle exist in coaching material, but they act on the joint differently; if the enclosed arm is not being extended, name what you are actually doing and ask your coach whether it is still sankaku-gatame.
13 / YOUR NEXT PRACTICE
One session: hook first, roll second
Task: with your coach’s agreement, run stages 1 and 2: build the triangle on a still uke on all fours, then turnover only, with no arm work. Ten repetitions each side.
- Situation
- Uke on all fours, me at the head.
- My focus
- Feet hooked before my shoulders start to roll.
- What I noticed
- Where did my right thigh land? Did the hook hold through the roll? Did uke’s head travel with the shoulders?
- Coach question
- “When the triangle opens, is it my first leg, my second leg, or uke’s shoulders?”
- Next decision
- Repeat the session, or add stage 3 (isolation and slow extension).
A worked review record
Illustrative example, not measured training data: “Ten triangles on the right side. The hook held on seven. On the three that opened, my right thigh was behind uke’s arm, not on the shoulder. In the turnover set, uke posted the right hand twice and I stopped as agreed. Once uke said the neck felt tight; the coach moved my thigh toward the shoulder. Next session: thigh on the shoulder line, and ask about the neck before every roll.”
The note records event, cause and change, and logs the neck report as information rather than failure. Keep it in the practice-log template or Judo AI so the next session starts from the leg placement.
14 / SOURCES & REVIEW
Sources, authorship and review
- Kodokan: Names of Judo Techniques (list dated April 1, 2017) — official name, kanji and position as the ninth kansetsu-waza.
- IJF: Sankaku-gatame definition and technique library — definition quoted in section 1; checked October 14, 2026.
- KODOKAN: 腕挫三角固 / Ude-hishigi-sankaku-gatame — identity and publisher verified by oEmbed; sampled frames viewed, not analysed shot by shot.
- welcomematstevescott: UDE SANKAKU GATAME Straight Armlock Using Triangle Control With Legs — identity, publisher, date, length and description verified; action not analysed.
- IJF replay listings: Reid and World Championships Senior 2019 — listing and tag only.
By Judo AI · Editorial review: October 14, 2026. The leg routes, the hook, the possible starting sides and the hand finish come from the IJF definition. Which arm is extended, the order of the legs, the roll, grips used to turn uke, the elbow’s resting place and the release order are commonly taught details flagged for coach confirmation. The drills, diagnoses and stage criteria are Judo AI editorial suggestions for supervised practice and have not been tested as a programme; review by a named judo coach has not yet taken place.
Rules and safety scope: this is a study guide for supervised judo, not a refereeing manual. We have not completed a current-rules review, including any rules on neck and spine pressure from triangle positions; check current IJF and event rules, and your age group and grade restrictions, with your coach before using kansetsu-waza or triangle controls in randori or shiai. Tap means immediate release in every context.