Kiyoshi Takayama, the No. 2 man in the top underworld syndicate Yamaguchi-gumi, was sentenced to six years in prison Friday for extorting ¥40 million from a construction business operator.

Takayama, 65, who heads the Nagoya-based Yamaguchi-gumi affiliate Kodo-kai, was given the sentence by a three-judge panel at the Kyoto District Court.

He had pleaded not guilty and denied he had any intention of extorting cash from the 67-year-old businessman.

Takayama, in conspiracy with other Yamaguchi-gumi gangsters, was charged with carrying out the extortion in 2005 and 2006.

During the trial, the victim testified that Takayama had forced him to work under the influence of the mob. Presiding Judge Akihiro Ogura, in handing down the decision, said the victim's testimony was reliable.

Among the conspirators was Yoshiyuki Takayama, 56, who heads Omi-Ikka, another Yamaguchi-gumi affiliate, based in Otsu, Shiga Prefecture. Yoshiyuki Takayama is also standing trial for extortion.

As of the end of 2011, Kobe-based Yamaguchi-gumi's ranks numbered about 31,000, or 44 percent of the country's gangster population of 70,300, according to police data.