As I mentioned on another thread a while back, I was in Tokyo in the 90s when the Iranians became a problem. They came to Japan on temporary work visas and overstayed, often engaging in illegal activities. Near Ueno Park where they had their dens was known as Little Tehran. One dawn, EVERY cop on the country closed in on them, shoulder to shoulder. EVERY Middle Easterner was detained and if they had no visa or their visa was expired, they were deported.By that evening almost ALL the crime stopped.
The cliche in the Western Media is that Japan's population will decline by half in 60 years, its economy will crash, and the country will implode unless they open their immigration floodgates. Absolutely false. Japan is a homogenous culture and seeks to maintain its homogeneity as it is the basis of their social order and a peaceful society. As a nation, Japan will still be around long after the US has come and gone.