Navy Order No. 1
5 November 1941
Order to: Yamamoto, C in C, Combined Fleet
1. In view of the great possibility of being compelled to go to war against the United States, Great Britain and the Netherlands in the cause of self-existence and self-defense, Japan has decided to complete various operational preparations within the first ten days of December.
2. The Commander-in-Chief of the Combined Fleet will make the necessary operational preparations.
3. The details of the operation shall be directed by the Chief of the Naval General Staff.
By Imperial Order
Chief of the Naval General Staff
(JAPANESE MONOGRAPH NO. 97)