How are armlocks categorised in Judo?

Question

I had always thought that the distinction between ude-garami and ude-hishigi-...-gatame was that the former attacked the elbow/shoulder joints by hyper-abducting the elbow/hyper-rotating the shoulder (necessarily with the elbow bent), and the latter hyper-extended the elbow joint (necessarily whilst straight).

However the Kodokan Judo Katame-Waza Techniques video demonstrates multiple examples of armbars (that I would previously have called ude-hishigi-ude-gatame) in its section on ude-garami:

It seems that it is implying the defining point of ude-garami is the figure-four position of tori's arms, not the mechanics of the pressure applied to uke's joints.

Is this accurate? If not, how are armlocks categorised?

Answer 1

The Kodokan classifies armlocks according to the position tori adopts while applying them.

As such this lock (sometimes called kannuki-gatame) is indeed a variant of ude-garami, since tori holds uke's arm in place with an "entangled" figure-four position.²

This methodology for classifying armlocks can be seen in the other examples in the same video:

1. Same biomechanics, different names

The Kodokan gives different names to an armbar¹ depending on which part of the body tori uses as a fulcrum/to secure the lock, despite them all attacking the same joint in the same direction:

• ude-hishigi-juji-gatame
• ude-hishigi-ude-gatame
• ude-hishigi-hiza-gatame
• ude-hishigi-waki-gatame

2. Different biomechanics, same name

Contrastingly, the Kodokan gives multiple different types of joint-lock (e.g. hyper-extending the elbow, abducting the bent elbow, hyper-rotating the shoulder) the same name, determined by the body parts tori uses to control uke's arm/as a fulcrum for the lock:

• Te-gatame refers to:
  1. armbars, where uke's arm is held in position with both hands
  2. hammerlocks, where the shoulder joint is hyper-rotated by holding uke's arm bent against their back with the hands
  3. bent elbow-locks, secured with only one hand (instead of two in a figure-four position as in ude-garami)
• Ude-hishigi-hiza-gatame refers to both:
  1. armbars secured with tori's knee
  2. bent elbow-locks (hyper-abduction) using the knee as a fulcrum
• Ude-hishigi-hara-gatame refers to both:
  1. armbars applied at the waist
  2. bent elbow-locks using the waist to trap the joint/as a fulcrum
• Ude-hishigi-sankaku-gatame refers to both:
  1. armbars applied from a triangle
  2. bent elbow-locks applied from a triangle

---

Notes:

^{1. armbar = straight elbow-lock = hyper-extension of the elbow-joint}

^{2. Given the wide array of joint-locks which fall under the blanket of ude-garami, one may wish to distinguish the variants further with more specific (non-Kodokan) names:
• normal ude-garami (abducts elbow, laterally hyperrotates shoulder)
• reverse ude-garami (adducts elbow, medially hyperrotates shoulder)
• kannuki-gatame (hyperextends elbow)}