How would you just consider a volume fake ?
There is nothing fake about it cause that is exactly what is happening. The fact that JPY is the most used currency in trading bitcoin, it does mean it is the country that trades most in BTC as we will never know.

Aside this, since their regulation and since the Chinese shutdown of exchanges, most of these traders found the closest neighbor and started trading JPY instead which I feel was what made JPY to be the highest right now.