Here’s evidence of child abuse–The underpants of the little girl yanked down on national TV by the of hand of her father showing the child’s bruises.

Japanese, and indeed most people in East Asia have a big blue birthmark on their lower back and buttocks. It looks like a huge bruise. It disappears in childhood (often before age 5), but some people keep it into adulthood.
The scientific term is Mongolian macula.