Are Hammerlocks legal in judo?

Question

The Kodokan Kansetsu-Waza video demonstrates a number of variations of te-gatame where uke's arm is pulled up their back, applying a hyper-rotational lock to the shoulder (sometimes called a hammerlock or chickenwing). In fact, all variants it describes (except for the first performed from standing) appear to be shoulder locks:

Unlike with other explicitly banned techniques demonstrated in the video (e.g. ryote-jime with the legs, ashi-garami, do-jime, daki-age), the commentary makes no mention that these locks are illegal.

Such techniques have occasionally been used in high level competition, but there seems to be inconsistency on whether hansoku-make is given.¹

Are these variants of te-gatame legal?

I had always assumed not, since they seem to be explicitly targeting the shoulder joint, but the ban on joint-locks anywhere other than the elbow was in place long before this video was published, and ude-garami is permitted as a long-established judo armlock despite also targeting the shoulder. Note also that the IJF explicitly lists te-gatame among their recognised techniques (code TGT).

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^{1. Hansoku-make GP Düsseldorf 2017 | Heinle vs Khammo | 100+ (switch camera to "Tatami 1")}

Answer 1

The Kodokan considers both armbar and bent arm arm-locks "locks applied to the elbow joint", since both involve locking the elbow joint to achieve their effect (locked straight and inverted, or locked bent and twisted), regardless of the point of pain/hyper-mobility exercised on uke itself.^{1 2 3 4} This includes hammerlock te-gatame, as well as omoplata style ashi-gatame and kimura ude-garami.

However, hammerlock te-gatame is considered illegal by some IJF referees. The Kodokan consider this a misunderstanding⁵ of the rules on kansetsu-waza:

Also, Tori who was trying to apply Ude-hishigi-te-gatame was given penalty as it was considered as an attack to Uke’s shoulder, with the current tendency of overreacting to hazardous actions. These seem to be caused by lack of knowledge rather than insufficient referee skills.

• Year Beginning Impressions (Jan 2019)
  Haruki Uemura, President of the Kodokan (original)

While it has been awarded ippon in 6/7 occasions I can locate of it being used in IJF competition (with 3 of these appearing on the IJF's own technique example page):

Event	Decision
Dusseldorf Grand Slam 2020 | Lkhagvasuren vs Keldiyorova	Ippon
World Championships 2019 | 48kg | Munkhbat vs Ungureanu	Ippon
Zagreb Grand Prix 2019 | Zupancic vs Prokopenko	Ippon
Tbilsi Grand Prix 2018 | 52kg | Babamuratova vs Delgado	Ippon
Guangzhou Masters 2018 | Tamaoki vs Roper	Ippon
GP Düsseldorf 2017 | 100kg+ | Heinle vs Khammo	Hansoku make
World Championships Astana 2015 | 63kg | Tashiro vs Urdabayeva	Ippon

Recently, Neil Adams during an IJF event demonstrated that under his understanding of the rules, a kimura ude-garami is legal, and a hammerlock te-gatame is illegal, the distinguishing point being whether tori has an arm entanglement grip:

I think ude-garami is allowed if it's an entanglement.

Note that the IJF Referee Commission consider hammerlock style te-gatame (as well as omoplata style ashi-/hiza-gatame) permissible as turnovers in ne-waza:

• IJF Refereeing & Coaching Seminar 2018: Day 2 (3:14:10)

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Notes:

1. te-gatame... Alternatively use one or both hands to grip your opponent's wrist and twist it around behind him to control his elbow joint.

   • Kodokan New Japanese-English Dictionary of Judo

2. Ude-hishigi-te-gatame | Hand armlock

   ... It is also possible to grasp his wrist with one or both hands and apply a lock to his elbow by twisting his arm behind his back.

   • Kodokan Judo: The Essential Guide to Judo by Its Founder Jigoro Kano (1997)

3. Kodokan Katame-Waza: Various Techniques and their Names (1994) (1:15:05)

4. Kodokan vs IJF rulesets:

   Japanese	Translation
   「腕緘」や「腕挫腋固」などで肘を攻撃していても、肩関節に影響を与える場合がある。明らかに肩が攻撃されて、相手が試合をする能力を失った場合は、負傷させた方の試合者が「反則負け」となる。	Even if the elbow is attacked with "Ude garami" or "Ude hishigi waki gatame", the shoulder joint may be affected. If the shoulder is clearly attacked and the opponent loses the ability to play the match, the injured player receives "hansoku-make".

5. This is perhaps understandable given the inconsistent way in which the term 'joint-lock' is used in different martial arts and languages, sometimes referring to the action of 'locking' a position, and sometimes the point of pain inflicted in the locked position.

   In addition to the general issues in translating technical and anatomical terminology from Japanese to English, I suspect the confusion is in part also due to the ambiguity of terminology for individual joint-lock names, referring variously to:

   • the point of articulation/pain in uke when applied (Achilles-lock, wristlock, biceps slicer, omoplata)
   • the articulation/movement of tori when applying (ude-garami, double wristlock)
   • the articulation/movement of uke when applied (armbar, chicken-wing)
   • or a combination of the above (ude-hishigi-hiza-gatame, knee-bar, toe-hold)

Answer 2

I will answer as best I can, but I expect more experienced referees may disagree.

This is an example of when the Kodokan classification is not very useful given the very different applications it covers.

First the Kodokan video:

1. Legal. This is a straightforward hyperextension armlock with tori's arm as the fulcrum.

2. Unsure. I am not familiar with this armlock, and the video is also not particularly illuminating either. Best guess is illegal because of the shoulder.

3. Illegal. I would call a hansoku-make on the armlock shown in the gif on the basis that it affects the shoulder and not the elbow.

4. Legal. This is basically an ude garami with applied only one hand, which is legal because it can affect the elbow.

And the video link:

1. Illegal. I think this is the Kodokan #3 from above, so illegal.

As demonstrated by the referee seminar, decisions can be very difficult, even with slow motion and instant replay.