heavy cruisers Chikuma Tone Takeo Yoshikawa I-72 Kidō Butai Niihau Pearl Harbor Imperial Japanese Navy cruisers
Before the attack commenced, the Imperial Japanese Navy launched reconnaissance floatplanes from heavy cruisers Chikuma and Tone, one to scout over Oahu and the other over Lahaina Roads, Maui, respectively, with orders to report on US fleet composition and location. Reconnaissance aircraft flights risked alerting the US, and were not necessary. US fleet composition and preparedness information in Pearl Harbor were already known due to the reports of the Japanese spy Takeo Yoshikawa. A report of the absence of the U.S. fleet in Lahaina anchorage off Maui was received from the Tone's floatplane and fleet submarine I-72. Another four scout planes patrolled the area between the Japanese carrier force (the Kidō Butai) and Niihau, to detect any counterattack.
