TOKYO — For six years US General Douglas MacArthur was lord of all he surveyed as supreme commander of the Allied forces in occupied Japan, gazing over Tokyo from a building requisitioned from an insurance company.

Now, more than 60 years after Japan began governing itself again, his office is being opened to the public, just as he left it.

The sixth-floor room has the original seats, desk and even an armchair where MacArthur would have sat as he presided over Japan's rise from the ashes of World War II.

From the office, MacArthur oversaw the transformation of a country that waged a brutal war of acquisition across Asia into a peaceable nation that would become the economic powerhouse of the late 20th century....