[johnwalkr]

Super interesting topic. Sometimes Japan uses the simplified version, or somewhat in between. Off the top of my head I only can think of 学/學.

There’s a handful of kanji created in Japan (called) kokuji, mostly food related. Some of these made it back to China. And there are a few differences based on simple mistakes, for example a Chinese character mistakenly applied to the wrong species of fish.

[xelxebar]

Just to add to this, simplified forms are mostly confined to Joyo kanji. The old forms do, however, exert their existence even in modern kanji as sub-pieces of (mostly rarer) other kanji---e.g. 専 used to be written 專, which still exists as the right half of 慱.

Also, there are lots of cases where the "simple" modern form doesn't really seem all that much simpler when viewing it in a typeface. My ad-hoc hypothesis is that these simplifications were considered with handrwiting in mind, e.g. 戻 (modern) vs. 戾 (original).

[glandium]

See https://en.m.wikipedia.org/wiki/Shinjitai#Inconsistencies My own goto example of these inconsistencies is 臭 vs. 嗅, aggravated by the fact that Chinese fonts will have the extra stroke in 臭.

[gumby]

This kind of thing happens with lots of language combinations as well, when loan words or Ana logical words embed themselves locally with different semantics.

You can even see this within a language e.g. UK/USA/Australia or Portugal/Brazil.