KOBE -- Kenichi Shinoda, the Yamaguchi-gumi's No. 2 man and a former gang boss in Nagoya, formally became the sixth boss of the nation's biggest crime syndicate in a ceremony Saturday at its headquarters in Kobe.

The ceremony, marking the first change of power for the Yamaguchi-gumi in 16 years, was attended by some 100 leaders and members of affiliated groups from across the country, while a number of plainclothes police officers patrolled the neighborhood.

Shinoda, 63, also known as Shinobu Tsukasa in underworld circles, is believed to have exchanged cups of sake with subordinates attending the ceremony, according to a source familiar with mob affairs.

The Yamaguchi-gumi traditionally holds such a ceremony to mark a change of power, which is intended to establish "quasi-blood relations" between the new boss and his subordinates, the source said.

Shinoda became the Yamaguchi-gumi's No. 2 man in May and was appointed the sixth don of the group in July, replacing Yoshinori Watanabe, 64.

Watanabe, who has ruled the Yamaguchi-gumi since 1989, announced last year he was "taking a rest" from his post as don after the Supreme Court ruled in November that he was legally responsible for the accidental shooting of a police officer by an affiliate gang member in 1995.