For those that don't know, the Judo takedown that Chonan did on Silva is known as a Kani-Basami. While it looks good and is very effective, it is extremely dangerous and has resulted in numerous broken bones. It was banned in international judo competition a few years ago but it is still taught.
Here's the technique:
One of the 67 official judo throws, but in my opinion, it should not be allowed in MMA. The last thing we need is bad publicity for MMA when someone gets their leg broken in dozens of places (if you don't believe that this happens with this technique, there was a long thread about it a number of months ago on the Judo forum).