https://www.nimh.nih.gov/health/statistics/suicide
Which looks like 5 per 100000 for 10 to 14 year olds?
The Japanese population in this age range is ~5M:
https://en.m.wikipedia.org/wiki/Demographics_of_Japan
So at the US rate we’d except ~250 suicides in Japan if the rate was the same as the US.
Over the 12 to 15 range in Japan the article states there were 103 suicides.
The rates seem roughly comparable therefore?
It terrible that this is increasing, but it would be interesting to understand if this is unique to Japan or not.