>The tradition of lovers ending their lives together, called shinjū

Lover suicides we're not a tradition.

I never heard of it before today so know nothing about it. Wikipedia has an extensive discussion of it, https://en.wikipedia.org/wiki/Shinj%C5%AB.

Is this page false with bad references maybe, or was it just a literary tradition and not happening in the real world?

Wiki suggests otherwise: https://en.wikipedia.org/wiki/Shinjū