The content of the talks, between the emperor -- known as Emperor Hirohito before his death in 1989 -- and Gen. Douglas MacArthur and his successor Gen. Matthew Ridgway, is described in an unpublished memoir the Asahi Shimbun has just obtained.

The memoir was written by Akira Matsui, a Foreign Ministry official who worked as the emperor's personal interpreter between 1949 and March 1953. Matsui died in 1994 at age 86.

At talks in November 1949, the emperor expressed his concern that communism could spread to Korea and Japan, according to the memoir. MacArthur pledged not to expose Japan to an invasion by communist forces, suggesting the need to station U.S. and British forces on Japanese soil as a temporary measure, it said.

It was the first time that the United States had conveyed to the emperor the security arrangement that it had been conceiving for postwar Japan, the newspaper said.

At their last meeting in April 1951, the emperor thanked MacArthur for objecting to trying him as a war criminal at the Tokyo war crimes tribunal, the daily said.

According to the memoir, MacArthur had questioned the concept of a war tribunal from the beginning and told U.S. leaders when asked for his opinion on the matter that he opposed trying the emperor at the court.

The notes show the emperor had been given in-depth briefings on the Korean War, which was unfolding at the time, and asked Ridgway in May 1951 if the U.S. would use nuclear weapons on the Korean Peninsula. Ridgway replied that the decision was up to the U.S. president, the paper said.

The memoir said that before a peace treaty was signed in 1951, Ridgway told the emperor that Japan needed to defend itself once it regained sovereignty. The emperor acknowledged the need, adding that the question was when and how Japan should implement it, the daily said.