When he was elected president by a rubber-stamp electorate in 1981, he promised not to seek a second term in accordance with the basic law, which permitted only a single seven-year presidential term, a legacy of previous dictatorial presidents.

The dossier released by the foreign ministry showed that Chun regretfully said in 1986 that, if he had not made such a promise, the opposition parties would focus on demanding he uphold the constitution, not going so far as calling for a change to the presidential electoral system.

"In hindsight, I have one mistake I made because I was not an experienced politician," Chun told then US State Secretary George Shultz who was visiting Seoul, according to their recorded conversation contained in the 30-year-old document.

"I should have not promised a single term. If I had not made the promise public and kept it only in my mind, now the opposition bloc should be demanding that I abide by the Constitution," he said.

The following year, Chun accepted the proposal for a direct vote in the face of a massive popular uprising, which marked Korea's historic transition to democracy.

Roh Tae-woo, one of the coup leaders, was elected president in the country's first democratic election in 1987. (Yonhap)