South Korea's spy agency has admitted it abducted future President Kim Dae-jung in 1973, with tacit backing from then leader Park Chung-hee.
Mr Kim was regarded as a dissident, but later became president
The admission came after a three-year inquiry by the National Intelligence Service (NIS) into its past conduct.
Agents snatched Mr Kim, who had lost an election to Mr Park in 1971, from a Tokyo hotel. They reportedly took him away in a boat intending to kill him.
Reports say the abduction was foiled after the US intervened.
The NIS said in a report: "This committee confirms that its precursor, the Korea Central Intelligence Agency (KCIA), undertook a kidnapping in Japan, and expresses deep regret over this."
The kidnapping, on 8 August 1973, is one of South Korea's most infamous events.
Mr Kim has said in the past that he was loaded into a boat with agents whose plan was to throw him overboard.
Mr Kim (R) became president and held a summit with Pyongyang
Most reports of the kidnap say Mr Kim's death was averted by the timely arrival of a US plane, which overflew the boat and scared the abductors.
The NIS report said that there was "physical evidence to support the possibility that, up to a certain point, the plan had been pursued as an assassination".
After the reported US intervention, Mr Kim was taken to the South Korean capital, Seoul, where he was placed under house arrest by Mr Park's government.
Mr Park "at least gave a passive approval" to the plan, the report said, but the panel could not prove he directly ordered the kidnapping.
Mr Kim was kept under house arrest and in prison for several years after that, but re-entered politics as South Korea moved from military rule to democracy.
He was elected president in 1997 and later won the Nobel Peace Prize for his policy of engagement with North Korea.
He walks with a limp because of injuries sustained in 1971 when a lorry ran his car off the road - an incident widely viewed as another attempt on his life.