#16 is Sumi Otoshi or the corner drop.
I love this technique. I find so much variation in it. Some people perform it so complexly that it almost becomes a theory throw, or an art throw. Other artists use it so simply and effectively that it becomes a standard tool in their arsenal.
If there is so much variation, how can we define it?
I see the floating techniques as a dance between centers, or haras. If Tori's center is dropping towards nage's outside (soto) - likely you might have a sumi otoshi.
Imagine a man standing in front of you. He has one foot forward, as in a fighting stance. Now imagine we tie an anchor on to his belt - with the chain about 6 inches too short to hit the ground with out him bending his knees. Yep, we are going to toss that anchor to try knock him down.
But where can we toss the anchor to make it a sumi otoshi?
Look at his feet. We have to imagine a triangle. His two feet make up one line of the triangle. Imagine the tip of the triangle behind his feet - roughly where his butt would go if he sat down backwards.
Throw the anchor and see what happens. Sumi Otoshi!
What? you don't usually have time to tie an anchor on to your sparring partner? Use your center as the anchor! Any connection will do...hands, arms shoulders..etc
I don' care for the fiddly how to part of techniques. I prefer to look at the generalized principle behind how it is supposed to work. There are probably a hundred techniques that could be considered a sumi otoshi. I don't think the fall uke takes is important. In some versions they will be spun around and take an airfall. You can be kind and let them roll. In all the versions I currently do, uke takes a back fall.
Let's look at some.
here is a classic Aikido version
This next technique looks very different. Everything the arms are doing is different. The connection is different. But somehow he is doing the exact same thing - sumi otoshi.
(I chose this video because this is kind of like how my Judo teacher Matl Sensei teaches Sumi Otoshi. The teacher starts demonstrating it at 48 seconds in and goes until 1:48)
Finally here is a classic Judo version. Personally I think this version looks to hard to actually hit easily, but I want you to see the drop towards the outside to understand the principles that make all these techniques fall under the same category.