[ 日 + 中 ] Simplified characters
Who came up with it first? Like Japan and simplified Chinese have some identical characters since they both simplified in the mid 20th century. Eg: 区 学 国 猫 etc etc But who copied who? Did the Japanese come up with these characters first and the simplified Chinese copied? Or vice versa?
Very good question. Shame that people don't seem to understand it.
Look up Shinjitai.
There was little cooperation between the Chinese and Japanese when creating Simplified Chinese and Shinjitai, so I don't know if in the case of 国 etc. they are the same because of coincidence or because one copied the other. Generally, the simplification is based on how the characters are written in handwriting, which often reduces the number of strokes in predictable ways.
This was part of a huge process in which the inevitable goal was to eventually use an alphabet like other languages, and there were actually two later simplifications in that process that failed to catch on, so the current one in use is the first round of simplifications that were put out.
I don't know as much about the Japanese side of things, but I know some of the simplifications are the same, while they decided to simplify other characters in their own way.