The mammoth 61-volume set, which has taken 24 years to compile at a cost to the Japanese taxpayer of 230 million yen ($2.2 million) reveals little new hard evidence about one of the most controversial figures of the 20th century.
But it offers a largely sympathetic view of the man considered by some to have played a pivotal role in Japan's march to World War II, and by others as the helpless puppet of an out-of-control military state.
They depict a man who spoke out against the military commanders who had taken Japan into full-scale war against China in 1937 with the promise that the conflict would be short and that victory was assured.
But they also show a leader satisfied with triumphs on faraway battlefields.
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An increasingly militaristic Japan had invaded Manchuria in 1931, where it established a puppet government and a base from which to agitate against China's weak regime.
After being briefed about the fall of the city, Hirohito told military leaders to tell their officers and soldiers, "I am deeply satisfied by their courage in quickly bringing down the capital Nanjing."
Documents used in compiling the Hirohito record include information about how Japanese troops surrounded and attacked the city, but did not contain details of the massacre of civilians, Kyodo News reported.