Combined Fleet Operations Order No. 2
7 November 1941
Order to: Combined Fleet
First Preparations for War
Y Day 8 December. [3]
C in C, Combined Fleet
Yamamoto, Isoroku
[3]. This order was issued by C in C, Combined Fleet, after he had
received verbal notification from Chief, Naval General Staff, that 8
December had been tentatively selected as "Y" Day.
(JAPANESE MONOGRAPH NO. 97)