Emperor Hirohito, the demi-god at the apex of the Japanese state when it waged bloody war across Asia, cautioned against conflict but celebrated military success, according to the long-awaited official history of his reign, released on Tuesday.

The mammoth 61-volume set, which has taken 24 years to compile at a cost to the Japanese taxpayer of 230 million yen (HK$16.92 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 the second world war, and by others as the helpless puppet of an out-of-control military state.

The annals, produced by the Imperial Household Agency, show how in the lead-up to Japan’s surprise attack on the US fleet at Pearl Harbour in December 1941, Hirohito warned against a “reckless war” that would make him feel “deeply sorry for my imperial ancestors.”