https://www.youtube.com/watch?v=dMEm8KAuD3c <- my source
1. The nips displaced the Ainu people (I heard they were an entirely new race @Sectionalism )
2. They stole everything from China
3. Their media is overrated, Anime is a limpwristed attempt at hero novels (well thats not even why as schopenhauer says to get famous just write for fools, it a cultural export) their characters look scrawny, but DB is ight but thats inspired from Chinese works (but as I said Europe/ME/China has more superior heros like Don Quixote, Gilgamesh, or Shennong)
Some pluses though is that they adapted quickly + quite homogenous
Updated