>>507604541
Japanese people are genetically distinct from Chinese, with an entirely distinct language and culture predating Chinese influence. Japan first settled by Jomon people estimated as far back as 14,000 to 8,000BC, later mixed with Yayoi peoples (Distant Manchu/Koreanic) who made their way to the island around 300BC-300AD. That's the first real mainland influence, and in itself only sinitic via influence on Machu/Koreans. In all that time you have 8000 years roughly of home grown native japanese culture, language, aesthetics, and don't start REALLY seeing Chinese influence until the heian period starting in the 700s AD. From that point yeah a lot of Chinese aesthetics and food and tech and also cultural elements come in but they're more or less reserved to the higher classes. To this day plenty of japanese foods have no root in china, Natto, Wasabi, Fish dishes, onions based stuff, etc, there's also a pretty obvious distinction in architecture between native japanese styles (brown, woods, greens, earth tones, tatami, simple designs) and Chinese influence (Red (cinnabar), gold, black laquer works, porcelain, ornate geometric designs, etc)

Tl;Dr: japs were in mudhuts basically until the 3rd to 4th century or so, but completely distinct from Chinese, albeit maybe some bleed through influence via Korea. Chinese influence doesn't really happen until the 8th century and even then remains a high caste thing, and the style blends a bit with several "re-japanization" movements up until modernity.

The only really "Chinese" based cuisine in modern Japan I can think of is like. Ramen? You'd be hard pressed to try to convince me that Sushi or pic related are remotely chinese