Interesting looking documentary on Japanese Karate from a former Kyokushin champion. Not watched it through yet so don't know how much practical karate discussion is involved, however it looks to have decent production values and may be of interest.
Same guy seems to have done a bunch of other documentarys called 'samuri spirit' looking at other Japanese Martial Arts. I've linked to the Judo one below which seems to have some interesting discussions on Japanese Judo vs Western Judo. Plenty more on youtube.