In a manga, a spectator is describing the way a boxer throws his punches:What is the meaning of 拳の山の骨? Does it refer to the knuckles? Here you can see the page it is taken from. Thank you for your help! Japanese Language Stack Exchange is a question and answer site for students, teachers, and linguists wanting to discuss the finer points of the Japanese language. It only takes a minute to sign up. Sign up to join this community拳 is "knuckle", so 拳の山 should refer to a part of a knuckle. Judging from the picture, 拳の山 seems to refer to the protrusion made by the metacarpophalangeal joints. 拳の山 is not a well-known term at least among laypeople. It doesn't look like boxer jargon, either. so perhaps it's a made-up word. Some orthopedists seem to use this phrase. Anyway, this is not to be memorized but to be understood ad-hoc.