Second or third generation Japanese are not generally accepted by the mainland Japanese.
After Korea, my Dad was stationed in Japan where I learned what “Nisei” and “Sansei” meant, referring to the Americans among us who spoke no Japanese and bore only an ethnic resemblance to the local populace.
Later on when I learned the history of the 442d Regimental Combat Team in WWII, the heroics of that unit became easier to understand when I recalled the Nisei folks I had known.
Japan is Japan, and it is a very different place & culture from the rest of the world’s peoples of Japanese ancestry.