Japan’s suicide rate is actually one of the most garbage data points we can discuss in this space, because their data is tremendously cooked. Check out this fascinating article from the LA Times I stumbled on while doing research for mine:
Japan's police see no evil
A drive to keep crime statistics low often fosters an official aversion to autopsies, critics say. TOKYO - Photos of…
I think, if you’re going to use modern numbers, you should probably look at South Korea’s rates, which are currently reported far higher than Japan’s, but are probably reported more accurately. I reference these in another article.