Climb Mount Niitaka
The Pearl Harbor Strike Force under Vice-Admiral Chuichi Nagumo (Nagumo, Chuichi) assembled in the Kuril Islands and, after a delay, sailed on 25 November 1941. Strict radio silence was observed by the force and all signals were made by flag or signal light (or blinker). They were in receipt of signals from Japan, picked up by the battleship Hiei and relayed visually. On 2 December the final decision was taken in Tokyo to go to war and the signal Niitaka yama nobore, 'Climb Mount Niitaka', was sent by Admiral Isoroku Yamamoto (Yamamoto, Isoroku) to Admiral Nagumo. It indicated that the attack was to proceed as planned.