Darren Kennedy wrote:
I've been looking at the final lock or pin of aikido moves and can honestly say that without a passive uke they do not work.
Well this depends on a few factors. First what pins are you applying? some of Aikido's pins have been "softend" so people don't complain as much during training. A good example of this is the Ikkyo pin as it is commonly applied, you just lay the arm down next to the person and hold it there with both arms, any able person will just roll over their own arm and get out from there.
However many of the pins if applied with attention to the shoulder, work well, you must also realize that you must be willing to brake the arm if they wiggle too much. In Juji gatami (common arm bar in both Bjj and Judo) if I were just to "hold" you there and not truly have intentions of braking your arm you could eventually wiggle out, even on a very skilled practitioner. Aikido's "pins" are much the same way, you cannot simply hold them there, and think you have an iron lock down on you attacker, you must threaten to brake if they wiggle, this is no different then Bjj or Judo submission holds.
The third factor is a weapon, I believe the main reason Aikido pins aren't body on (like say a wrestling pin, Bjj pin, or Judo pin) is because you need to keep your body away from the other hand. In Aikido pins you will generally control one arm fully (the one you know is armed) and stay away from and watch the other arm (the one that may be armed but you don't' know about yet), this gives you a superior blend of safety and control in weapons situations. If you want to see how this works, set up your friend in a Nikyo pin, and hold a knife to the back of his neck and see how much wiggling and escaping he can do them. Notice how O-sensei had a tegatana coming down at the end of most of his pins (probably representing a real katana).