On December 7, 1941, two hours after the Japanese attack on American military installations at Pearl Harbor, Hawaii, Japan declared war on the United States and Great Britain, marking America’s entry into World War II. The Japanese government had originally intended to deliver the declaration thirty minutes before the attack, but the Japanese embassy in Washington took too long to decode the 5,000-word document.

The declaration read, in part, that Japanese "officers and men of our army and navy will concentrate their strength in engaging in battles, the members of our government will endeavor to carry out their assigned duties, our subjects throughout the empire will employ full strength to perform their respective tasks. Thus uniting one hundred million hearts and discharging the fullest strength of the nation, we expect all our subjects to strive to attain the ultimate objective of this expedition." It was printed on the front page of Japanese newspapers on December 8, 1941, and again on the 8th of every month until the end of the war.

This copy of the declaration of war folds into an original blue cloth box imprinted with the document’s title.

A full translation is available.

Excerpt

We, the Emperor of Japan, having acceded to the throne of the unbroken line of emperors which is for ages eternal, with the divine providence of the heavenly god, hereby proclaim unto our loyal and valorous subjects:

That we, the emperor, have now declared war upon the United States of America and Great Britain. The officers and men of our army and navy will concentrate their strength in engaging in battles, the members of our government will endeavor to carry out their assigned duties, our subjects throughout the empire will employ full strength to perform their respective tasks. Thus uniting one hundred million hearts and discharging the fullest strength of the nation, we expect all our subjects to strive to attain the ultimate objective of this expedition.