According to the Sport and Organization Rules of the IJF (2019), the following applications of katame-waza are illegal:
Joint-locks applied anywhere other than the elbow (i.e. neck, spine,17 shoulder, wrist, hip, knee, ankle, finger,16 toe locks etc).1
The leg-lock ashi-garami is explicitly illegal.14
Exception: The shoulder-locks ude-garami ...
Yes, there are other constriction techniques. These are a few examples, not meant to be exhaustive. As a philosophical matter, I think you should always be looking to further break uke's structure and constrict their movement and breathing; this is maximum efficiency.
yoko shiho gatame: Tori is on the side with extended legs, one arm around the head, and ...
There are a few positions where you can finish multiple submissions simultaneously or nearly so.
If you look at the triangle as a position, then a lot of other submissions present themselves as co-attacks. The triangle-armbar is the classic; it's often unclear which one does the most work in any given case. The triangle-Kimura is also great fun.
Yes. From triangle (sankaku) positions, there is the standard choke with the legs as well as the option to apply armbars. For example, from this side triangle position, if the choke fails, you can either cross body armbar (juji gatame) the near arm, or Kimura (ude garami) the far arm.
In the YouTube comments, someone points out
Commenter "Gerijima" below says in japanese that the technique is called "itotoushi" (phonetically: ee-TOW TOW-oo-she) which in japanese means "thread pass through" as in the action of threading a needle. And he says this technique is in Shinya Aoki's book.
Discussed a little further ...
Yes, both strangles and joint-locks are traditional techniques in various schools of Indian wrestling.
However, in some schools there are restrictions on their use and they may only be employed as compliance techniques to manipulate the opponent into a pin (as in collegiate wrestling), as opposed to submitting outright (like in judo, bjj):
We find four ...
While the nutcracker analogy is useful, there is a subtle difference:
with a nutcracker, the stress is applied to the nut
with a compression lock, the 'nut' (limb you are using as a fulcrum) is supposed to sustain the stress and redirect it to the 'axle' (the opponent's joint)
Some basic newtonian concepts for improving the efficiency of your compression ...