idk how to post replays, but I have one:
Match length 400
Turn length 44
Engage distance 160
Extend both hips and both ankles
Contract both knees
Hit space
Contract the ankles
Extend the knees
Contracting the hips is optional - whether or not you do, it's a decap.
Basically, the fighter backflips and kicks the uke into the air, then the uke lands on his head hard enough to remove it. However, the Tori loses his head in the process, so it's a double decap.
Also, I'm not clear on the rules: Is holding allowed for the challenge, and does holding count as using a joint?