Japanese page is here.
What are the prohibited moves that result in an automatic loss?
They are the following eight moves.
- Punching with a closed fist
- Intentionally pulling hair
- Jabbing at eyes, solar plexus, or other vital parts
- Pulling both ears at once
- Grabbing the front section of the belt, or sticking one’s fingers in and pulling.
- Grabbing the throat
- Kicking the stomach or chest
- Bending back one or two fingers
In official tournaments, you will almost never see any of these moves. There have been cases, however, of pulling top-knots and grabbing at the front of belts. The main basis for judgment is whether the gyoji and judges feel the move was intentional, although they do not confer with the rikishi involved on this point.