To underline his concern that conservative ministers would invite international controversy with comments about Japan's role in the war, which ended 50 years ago next week, Mr Murayama issued a brief written warning to his cabinet: "Keep your comments within these bounds."
The Prime Minister, who replaced 16 of 20 ministers in his 14-month-old government yesterday, has been haunted by remarks on the war by right- wing ministers from the Liberal Democratic Party (LDP), the senior coalition partner.
Last summer Shin Sakurai, the Environment Minister, had to quit after saying that Japan's wartime actions were for Asia's benefit. Earlier this summer, Michio Watanabe, a former foreign minister and a senior LDP leader, provoked riots in South Korea when he said Japan's brutal 1910 annexation of Korea was the result of an "amiable" agreement.
Days after that, LDP conservatives dashed Mr Murayama's attempt to persuade parliament to pass a resolution apologising for Japan's wartime aggression in Asia.
After weeks of public feuding over the wording of the statement, the coalition produced a statement of remorse that was attacked throughout the region for its vagueness and timidity.
Among the new cabinet appointees are several LDP parliamentarians with strong nationalistic views, including Takeo Hiranuma, the new Transport Minister, the son of a pre-war prime minister who was convicted as a war criminal.
The shake-up was less radical than it appeared, with Mr Murayama retaining his key finance, trade and foreign ministers.
The only surprise appointment was that of Isamu Miyazaki, a private researcher at the Daiwa Institute, as Economic Planning Agency Minister. He is the only non-politician in the new cabinet.