A former president and two former managing directors of Nomura Securities Co. pleaded guilty Tuesday to conspiring to pay 370 million yen to a "sokaiya" corporate extortionist in one of the biggest financial scandals to rock the nation this decade.

Former Nomura President Hideo Sakamaki, 62, and former Directors Nobutaka Fujikura, 55, and Shinpei Matsuki, 53, are charged with violating the Commercial Code and the Securities and Exchange Law by giving payoffs to sokaiya Ryuichi Koike, 54, who also faces trial. Nobuyuki Koga, a Nomura director representing the brokerage for its Securities and Exchange Law violations, also pleaded guilty in the arraignment before the Tokyo District Court.

The Nomura trial is the first in a series of cases involving Koike's dubious ties with the Big Four brokerages and Dai-Ichi Kangyo Bank. Koike is scheduled to stand trial in a separate procedure next Tuesday. Each of the four defendants, all wearing dark blue suits, said, "(The indictment) is correct," when asked to reply to a judge's request to enter a plea.