Is track cycling a big sport in Japan

There are only a few legal forms of gambling in Japan. For sports gambling, there's only boat racing, bicycle racing and horse racing. They're not popular among the general public but for gamblers those are the only shows in town.

Yes.. cycling is huge in Japan.. they invented the Keirin around 1948.. now a permanent fixture in olympic track cycling since 2000.. where about 6 riders trail behind a motorized cycle as it speeds up..