The Japan leg of China's Olympic torch relay began Saturday with thousands of riot police lining the streets, helicopters buzzing the skies and demonstrators rallying in a pro-Tibet prayer vigil. Initial skirmishes among protesters and police failed to disrupt the passing of the torch. The starting point - a last-minute substitution after a famous Buddhist temple pulled out - was closed to the public, as were all rest stops along the way. Japanese officials said the security was unavoidable, and called for calm. But the high-profile police presence has dissipated any festive mood in Nagano, which hosted the 1998 Winter Games. The relay - making its 16th international stop - has been disrupted by protests or conducted under extremely heavy security since it left Greece. One person was hurt in a scuffle between Chinese and pro-Tibetan supporters, and a self-proclaimed monk carrying a knife was arrested hours before the relay began. National broadcaster NHK reported some kind of smoke-emitting tube was thrown at the relay, but there were no injuries or damage. After Nagano, the Olympic torch heads to South Korea on Sunday and then to North Korea on Monday. It then goes to Vietnam and Hong Kong.