Imperial Rescript to Soldiers and Sailors
The Imperial Rescript to Soldiers and Sailors (軍人勅諭, Gunjin Chokuyu) was the official code of ethics for military personnel, and is often cited along with the Imperial Rescript on Education as the basis for Japan's pre-World War II national ideology. All military personnel were required to memorize the 2700 kanji document.
Source: Wikipedia — Imperial Rescript to Soldiers and Sailors (CC BY-SA 4.0)