Even though joint locks (locks of the arm joints with both fighters standing upright for the purpose of this article) are not primary part of RW - partially because of the reasons outlined in the article - I studied them quite extensively in my younger years. In this article I want to share with you several information I think are usually missing in mainstream sources.
First and foremost, there is a confusion surrounding the role of standing joint locks in today's martial arts(but, as my training partner said recently, there is a confusion surrounding almost everything today):
Standing joint locks are either considered an 'effective self-defence technique'(by 'traditional' martial artists), or deemed unnefective and show-off techniques that cannot be applied in real fight(by 'modern' martial artists). Both these camps' answer are generally wrong, because they do not have the question right in the first place.
Let me put it straight - joint locks,by themselves are not a good self-defense techniques; for several reasons.
First, compared with other types of fighting techniques - punches,kicks,throws - standing joint locks are the most complex and difficult to apply. The timing,the force, the angles, all must be absolutely perfect for a joint lock to work. In other words, you must have a big advantage over your opponent, be it in skill, strength, him being injured or stunned etc before you should attempt a joint lock.
Second, even if they work, they are unpractical for basic self-defence. In the archetypal 'drunken uncle' scenario, using a joint lock that might end up dislocating a joint by accident is too much force. And if the fight is for real - what are you going to do after you get the opponent in the lock and he 'submits'? Will you let him go? Or will you break his arm? Really? How will the law look at a dislocated shoulder over a bar scuffle?
This should tell you that for self-defence, joint locks are unpractical.
On the other hand, are standing joint locks completely useless techniques, as proponents of mixed martial arts say(using their classic reasoning 'unless it is applied in the octagon,it doesn't work')?
Not really. The problem is at the usual place - in the context.
Imagine the context joint locks were developed in - the old China,for instance. The time before guns and handcuffs. Imagine being a policeman, or some other person who needs to restrain another person, possibly a criminal.
You cannot kill the guy; on the other hand, you cannot let him go. And he does not want to go with you. He is strong and probably agresive, and motivated to get from you. Without a gun and modern handcuffs, it is not a simple matter of clicking the cuffs on. At most, you have a rope. And you have to tie him,my friend; do you think he will hold still for you so that you can tie him up? Not very likely.
And this is precisely where the joint locks come in. In old Chinese and Japanese context, joint locks were a finalizing technique in a fight that lead to tying the guy up and transfering him away(the tying up techniques being taught too). The locks were not meant for you to dick around with them applied, trying to 'control the opponent'. The tactics were as follows:
Grab the suspect and get him in an arm lock
Injure the locked joint and hold him by it.
Tie him up, using the injured joint.
Note that injuring(not necessarily crippling,mind you) the opponent's joint is a part of the tactics.People who tell you that joint locks can be used to 'control opponent without hurting him' are selling you a fiction. In order for a determined person to let himself be controlled, the pain must be really tremendous - which means injury.
After you injure him, it is a whole different story - it is a lot easier to control a person holding a dislocated joint! Then you can use this control to tie him up and transport him safely.
This is the traditional modus operandi of 'standing joint locks'. By the way, techniques of tying a person up using a rope were part of the curriculum of original Judo, before they were deemed archaic and taken out. By removing the context of 'injuring,tying up and carrying away', standing joint locks become just a point of confusion; because by themselves, they are really useless. On the other hand, as a technique to setup the tying up, the were invaluable. They were meant for controlling, but they cannot be used to control people reliably by themselves.
This is why trying to use standing jointlocks as controlling devices is, to me, contrary to their design from the start. Not even aikido, a style renowned for fighting non-efficiency, does try to lock the joint and hold the opponent there. Instead, it uses the lock to throw or force the opponent on the ground, where he his pinned and re-locked. But this is a whole different type of control - ground pin;not a standing joint lock(type 3 and 4 from the Excursus II).
From a standing joint lock, a game opponent will probably wiggle out of after several seconds; or you will be forced to let go of it. So this usage of joint locks is indeed unrealistic - but at the same time, this was never how joint locks were designed to work!
This is a classic technique of the above type from Chinese Qin-na; it illustrates transfering from a joint lock to a position for tying up. First, the opponent's wrist is injured and controlled; then, shoulder lock hold is applied to force the opponent to the ground. Next, you step on his shoulder and butt the shin bone forward to dislocate the shoulder joint, before finally tying him up.
This article discusses the most usual usage of joint locks - for control. This is the modus operandi of vast majority of the joint locks taught in today's martial arts school (and as expressed above, it is impractical).
There are several other legitimate uses of joints lock in fighting, which are more usable for self-defence, that will be discussed some other time:
1) crippling - locking techniques that do not allow controlling the opponent for any length of time; only quickly (and seriously) damage a part of his body. They are used a direct method for opponent neutralization. These techniques are rarely taught in 'popular' eastern martial arts. Tony Cecchine in American Catch Wrestling calls these types of techniques 'hooks' - or 'knockout blows of submissions'; which I find appropriate.
And before you ask, their construction is a bit different than the common 'controlling' locks; their design not emphasizing control(=continuous application of force and controlling the COG), instead focusing on the amount of breaking force applied momentarily.
Example: 'strappado' of Seisan
2) breaking holds - joint jocks used for the immediate purpose of breaking opponent's hold on you. Again, there is not controlling and usually no injury involved.
Example: breaking a grip against the thumb
3) transitional - repositioning the opponent for a strike, or throwing him onto the ground. Again, only immediate action, not intended to control for a longer time; more of a 'takedown'.
Example: quick wristlock to throw opponent on the floor
4) ground locks - combination of joint locks with pins; where either of your is one the ground. A part of groundfighting; these locks allow a greated control because the opponent is generally pressed to the ground with your body.
Example: BJJ armbar
add the use number 5, discussed in this article:
5) injuring the joint and tying the opponent up to transport him - the subject of 'come-alongs' being beyond the scope of this article
And you have enumerated all the practical uses for joint locks.
Interestingly, in Mestre Bimba's Regional, there are (at least) three joint locking techniques; these do not fall into the 'controlling' tactics(see Excursus no II).
1) quebra mao - outside wrist lock
2) armiloqui - outside wrist lock coupled with a twisting elbow lock. In the sequence, it is followed by a 'guillotine' headlock, countered by a frontal arqueado.
3) quabra pescoso - not really a 'joint'lock; this consists of pressing elbow against the throat cartilage to crush it when opponent holds you in bearhug. (Combination of tactics 2 and 1).