At the start of the 1990s, when "world music" became a generally accepted term, some Japanese started to look at themselves and wonder what their own country had to offer -- not only in Japan but to the rest of the world.
The answer was very little. There was Okinawan music, but to many Japanese, Okinawa can seem quite distant, and even foreign. There was traditional music, but this had mostly been preserved like a museum exhibit and had become a classical music, with little connection to most Japanese people. Pop music, on the other hand, had lost virtually any trace of anything inherently Japanese.
Then there was Shang Shang Typhoon.