Despite the IJF prohibiting throws which 'may endanger or injure the opponent especially the opponent’s neck or spinal vertebrae', there are a number of throws where it is not uncommon 5 in competition for uke to hit the mat first with their head, or impact with it after falling, and which seem to fall under another clause in the IJF's rules where 'involuntarily' impacting the mat with uke's head does not incur a penalty for either party. The IBJJF specifically bans 1 two judo-throws where uke lands on their head/neck. In contrast, judo players will stop once elevated. For safety, I just tap and talk about it afterward. I do not personally train BJJ, but when rolling with BJJ players who cross train in judo, I have experienced that they just continue playing as normal when picked up in the guard or sankaku (triangle) positions.

See TABLE: Technical Fouls – Illegal Moves #16 Slam. In IBJJF rules, this is a slam and illegal. In judo, this danger is recognized as ending the matwork situation without the technique actually being applied. This is very dangerous because the impact is often on the head or spine, which can result in paralysis even without significant elevation. In a self-defense situation, the technique you would actually apply is daki age where you slam the opponent into the ground. Once you have them off the mat, a referee will call matte and reset the match from standing. In judo, to escape from your opponent's guard position, you can stand up and pick them up off the mat.

Jiu jitsu moves