While watching today's Hakuho vs Shohozan bout on Kimtamayama's excellent daily recap, it seemed from one angle of replay that Hakuho had at one stage put his knee in the groin region of Shohozan - not particularly hard, (and certainly not hard enough to change the outcome of the match), but it made me wonder whether this was an illegal move, along the lines of 'pulling the hair' of an opponent. According to wikipedia, it is illegal to grab or pull at the opponent's groin (which suggests to me the use of hands), and it is illegal to kick the opponent's waist or chest, but no mention is made of a quick, hard knee into the 'crown jewels'. How about the original Japanese (i.e. does the English translation of the various illegal moves for some reason not cover this)? Or would it (under the current laws of sumo) be legal to grab the opponent in a hold at the tachi-ai, then give them a quick knee into the 'Kintamayamas' before throwing down or shoving out the opponent with tears in his eyes?
(This reminds me of what I used to believe about sumo, before I started watching and reading about the sport. In the James Bond book, 'You only live twice', it asserts that rikishi can retract their prized possessions into safety within their body. Something that they train for from an early age.)