Last night at training we were playing with knives as we do every session. My partner was a karate guy (BB) with experience in grappling and aikido. He had the knife. We were both sweating so his wrist was quite wet and slippery, same as it would be if there was blood. I managed to control the knife hand but couldn't get a lock. (I probably could have got in a kick or punch but that wasn't what we were training.) Eventually we ended up on the ground where I had side control with my left hand controlling his outstretched right arm, holding his wrist. That was his knife hand. He has far greater grappling skill than me and was able to keep me in a position where I couldn't get much advantage. I finally got the knife by muscling it from his hand (who says blunt knives don't cut? ) but I feel that I should have been able to get a lock on his right arm somehow, something like a figure four. Any ideas?