This detailed technique post was written by 3rd-degree Roger Gracie Jiu-Jitsu Black Belt Nicolas Gregoriades.
When I first learned the Kimura, over 15 years ago, it was as a simple jiu-jitsu submission from the closed guard. As my journey into the art has progressed and my understanding increased, I have found it fascinating to discover that there is really so much more to this powerful hold. This attack might just be the jiu-jitsu move with more names than any other. It's also known as the 'chicken-wing', 'reverse key-lock' and 'gyaku ude-garami' - I'm sure there's even a few more that I'm missing. The 'Kimura' reference comes from the judoka Masahiko Kimura, who employed it to defeat legendary Helio Gracie in a match in the 1950s.
A great thing about it is that can also be used from almost any position. I've seen it used successfully from mount, guard, side-mount, half-guard, north-south and others. I have a couple of friends and training partners who are absolute masters at this - they're able to latch onto me with the hammer-lock from almost any position - guard, half-guard, side-mount, mount, the back - even underneath side-mount! Once it's engaged I know I'm in deep water. Not only am I'm constantly in danger of the sub, but most of the time it's almost impossible to gain any leverage as are able to control and manipulate my whole body with it.
Not only can it be used to submit an opponent, but it also has applications as both a sweep and a control method. I've pieced together an example of each of these into this video sequence. It features a really cool sweep from half-guard called 'the toilet-bowl' (yes seriously!) that I've been having a bunch of success with lately. One of my black belt students also won the European No-Gi Championships using it a couple of years back
PS - one detail about the sweep that I didn't know at the time I made the video is that as you push your opponent's arm up into his body to roll him over, you need to 'run' your legs away from him - almost as if you were intentionally trying to put yourself at the bottom of the North-South position. This stops him from using a tricky step-over armbar counter that can turn the bottom player really quickly.
Bonus Kimura Secret:
Tightness! It was when I finally understood this that the move became much more than just a submission for me. I started to realise just how good it was for control too. Before I even started jiu jitsu I used to train boxing quite a lot. My coach always used to tell me 'With a great jab you can rule the world'. Now I say to my jiu jitsu students 'With a great Kimura you can control the whole match.' When you engage your figure-four hold properly by using the tip in the video below, you can pretty much do what you want you want to your opponent.