We have been working on kimuras in class over the last couple of weeks. It's a common attack - the figure four grip is very difficult to escape from, so it also makes a great grip for transition to armbar.
You also have the option of a compression due to the grip setup - options are always good!
But finishing a full on kimura with the opponent turned on their side can be difficult. People are a pain in the ass when defending this attack. They will grab their belt, cup the inside of their thigh, or make an S grip to prevent the finish.
If they are flexible they can even get a foot in and begin to pry the grip loose (ala Jeff Glover).
Here are a couple of options when dealing with these types of common defenses.
1. Vandry Kimura
Setup: You have a full on kimura set up. The opponent is on their side, you are clamping their head with your knees, and they are utilizing one of the above mentioned defenses to prevent the finish.
In this variation, the opponent needs to be in somewhat of a fetal position, i.e. his legs need to be tucked up. If they are cupping the inside of their thigh (no gi) they will have to be in this position.
Pull the opponent in closer and then use your heel to hook behind your opponent's knees. Perform a 'crunch sit-up' motion. This will put so much pressure on his shoulder that he will tap, even if he never lets go of his defense.
2. Breaking the grip with your chest
Setup: Full on kimura setup - opponent on their side - figure four grip established.
You cannot break your opponent's defense grip with the standard options.
Pin your opponent's wrist of the arm you are attacking, then back away, making some space.
Come back in lower and position your chest against your opponent's tricep. Drive forward, keeping
the wrist pinned. This will create enough pressure on the wrist such that your opponent will be forced to release his grip - not necessarily due to pain - it's more of putting the wrist joint in a position that it cannot sustain strength. Once the grip is broken, pull the tricep to your chest and turn the wrist to properly finish the kimura.
Carter used to talk about making different parts of the body twist in different directions, making opponents uncomfortable and limiting their defensive options. Wednesday night, Josh showed how to use your knees to make an opponent's head look down as you go to finish the kimura. This puts more pressure on the shoulder joint - also makes it difficult for the opponent to get his back on the ground - another common defense against the kimura.
Josh also showed an interesting progression when attacking from the back. Perhaps you have a same side wrist grip, controlling one of your opponent's hands. You'd likely be attacking with a choke using your other arm. To transition to armbar/compression, you'll have to take one of your hooks out and lay the person down. Your choking arm comes over and you make a quick switch to a figure four grip. You can lock your ankles which prevents too much squirming. Eventually you'll bring your leg over your opponent's face. Since you have a figure four grip set up, you can attack with a compression - make sure the blade of the forearm is rotated correctly for maximum pain (make the thumb point up). Typical kimura grips are monkey grips (no thumbs) and way down on the back of the opponent's hand. When switching to a compression, you'll move up the forearm with the grip.