Batou is Japanese to the core. His entire backstory hinges on it. At least Google the character first.
Well, you can be Japanese and Caucasian... they are not mutually exclusive (one is a race, the other is a nationality). I've read the comic in the past, watched the original film, watched SAC and he has always been a white guy often with blonde hair. It's been well over a decade since I've seen anything in this series -- maybe, I missed something, but if you asked 100 people who've seen GITS, 99 would call Batou a white guy.