Thailand has always had its Japanese quarters, like Thong Lo and Ekkamai in Bangkok or Sriracha and Laem Chabang in Chonburi. These places are related to Japanese expats' work locations - commerce and so on in the capital, and port activities further south. I am not sure when the love affair with all things Japan took off though - but it is definitely a thing. It’s not just the franchised eateries like Fuji and Yayoi, now there are out-of-town malls like this one near Sriracha in Chonburi. J-Park offers you a total Japan experience, complete with the Don Don Donki supermarket which visually assaults as soon as you enter, and takes you all the way to Tokyo.