Why is ude-garami legal if it is effectively a shoulder lock?

Question

Since 1925, judo competitions have nominally banned all joint-locks applied "anywhere other than to the elbow joint". Since its inception in 1951, the IJF has also adopted this rule.

In spite of this, the shoulder-joint rotating¹ armlock ude-garami has remained a staple of kansetsu-waza for the past century, not uncommon at the highest levels of competition and consistently appearing in the IJF's list of recognised techniques.

Given the rules seem to prohibit shoulder locks, why is "bent-arm" ude-garami explicitly permitted?

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1. ^{Depending on the joint flexibility of a person, armlocks that hyperrotate the shoulder joint can also hyperrotate the elbow joint, and vice versa. [...]}

   ^{The Americana, (also known as... ude-garami/arm entanglement in Judo.) is a grappling keylock technique in which both of the practitioner's arms isolate and cause flexion to the shoulder, elbow, and to a lesser extent the wrist of the opponent. [...]}

   ^{Kimura... known in judo as gyaku ude-garami (reverse arm entanglement)... is similar to the Americana except that it is reversed... By controlling the opponent's body and cranking the arm away from the attacker, pressure is put on the shoulder joint, and depending on the angle, also the elbow joint...}

   ^{• Radiography of the Upper Extremities}

Answer 1

What is an "elbow-lock"?

While a common misconception, armlocks which cause pain to the shoulder are not inherently illegal in Judo.

The phrasing "kansetsu-waza applied to the elbow joint" is used by the Kodokan to describe joint-locks which achieve their effect by:

1. straightening or bending the elbow joint ("locking" it in place), and
2. stretching, bending, or twisting the arm to submit the opponent^{1 2 3}

The defining point is the manipulation of the elbow joint, not the location of pain in uke's arm.^{3 6} As such, ude-garami, as well as other bent-elbow, twisting armlocks (e.g. hammerlocks and omoplatas), have consistently been included in Kodokan and IJF descriptions of legal kansetsu-waza since the rule was last modified in 1925.

Legal kansetsu-waza in Judo

From a biomechanical perspective, legal kansetsu-waza includes:⁵

1. hyper-extending elbow ("armbar")
2. flexing elbow + hyper-rotating shoulder
   1. external rotation (+ abduction) ("Americana")
   2. internal rotation (+ adduction + extension) ("Kimura", "hammerlock", "omoplata")
3. hyper-ab/adducting elbow ("perpendicular armbar")

With the following shoulder-lock variants having been explicitly demonstrated as legal:

• ude-garami (Americana ^{from top}/_guard, Kimura ^{from top}/_guard)
• te-gatame (Americana, Hammerlock)
• hara-gatame (Americana)
• sankaku-gatame (Kimura)
• ashi-gatame (omoplata, reverse omoplata, Huizinga roll)
• hiza-gatame (omoplata, reverse omoplata, Huizinga roll)

Note that the arm is a complex machine of interconnected muscles, ligaments, tendons and bones - application of one style of armlock, especially against a resisting opponent, may incorporate multiple mechanics and sources of pain simultaneously.

History of kansetsu-waza restrictions

• 1899: Finger, toe, and ankle locks (ashi-hishigi) banned.^{7 10
  (Inaugural jujutsu competition rules drafted by Kano for the Dai Nippon Butoku Kai)}
• 1900: Wrist locks banned.^{8 10
  (Kodokan competition rules)}
• 1916: Finger-locks (again), ashi-garami, neck-locks banned.^{8 10
  (Do-jime also banned)}
• 1925: Restrictions simplified to one rule prohibiting kansetsu-waza applied anywhere other than to the elbow.^{8 9 10
  (Plus restriction on techniques which may endanger the spine or neck.)}

When the IJF was founded in 1951, it adopted the English translation of the Kodokan's competition rules for the first 3 decades of its existence (explicitly deferring to the Kodokan interpretation of these rules in any case of translation ambiguity):⁴

Applying "Kansetsu-waza" (Bonelocks) on joints other than the elbow ;

• Contest Rules of the Kodokan Judo (1948, 1951, 1955, 1961)

From 1983 onwards, the IJF published its own separate ruleset, updating it periodically. However the original kansetsu-waza rule has remained aligned with the Kodokan rule to this day:

To apply kansetsu-waza (joint locks) anywhere other than to the elbow joint.

• English Contest Rules of the IJF (1983, 1985)

To apply Kansetsu-waza anywhere other than to the elbow joint.

• IJF Refereeing Rules (1999, 2003, 2011, 2014, 2015, 2018)
• IJF Sport and Organization Rules (2017, 2019)

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Notes:

^{1. Kodokan Katame-Waza: Various Techniques and their Names (1994)}

^{Lock the elbow by straightening, twisting, or bending the arm... Straighten out or twist the arm to lock the elbow.}

^{2. Kodokan Judo: The Essential Guide to Judo by Its Founder Jigoro Kano (1997)}

^{Joint locks are directed against the opponent's joints, which are twisted, stretched or bent with the hands, arms or legs.}

^{3. The Kodokan New Japanese-English Dictionary of Judo (2000)}

^{ude-garami... use both arms to entangle one of your opponent's arms while twisting it to the outside our inside to control his elbow joint.
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.}

^{4. Contest Rules of The Kodokan Judo (1955)}

^{Note:- In the event of a disagreement between the original Japanese text of these rules and any translation thereof, regardless of the languages used, or any ambiguity in any such translation, the Japanese text shall prevail.}

<sup>5. Though to my knowledge never performed in international competition or demonstrated in any Kodokan material, this definition may also include hyper-flexing elbow-locks (i.e. Biceps slicers).
6. /r/judo US Referee comment
7. Judo: Japanese Physical Culture, Sumitomo Arima (1908)
8. Contest Judo, Roy Inman (1987)
9. Jigoro Kano and the Kodokan: An Innovative Response to Modernisation (p.109-111)
10. Development of Judo Competition Rules, Syd Hoare</sup>

Answer 2

I think you have mostly answered your own question.

Ude-garami can affect both the shoulder and the elbow joint. As an official, it is not possible to tell whether the shoulder is being affected. All you can tell is that a nominally legal technique is being applied, and uke either taps or they do not. The same technique motion applied to a different uke could result in a different joint being affected depending on flexibility.

While it is illegal to attack the shoulder joint intentionally, it is considered legal to affect the shoulder joint with ude-garami because the intention is to attack the elbow joint. This is non-ideal, but honestly I do not know how you could enforce ude-garami strictly against the elbow joint.