|Attack on Pearl Harbor|
|Approach and attack|
|Possible third wave|
Approach and attack
The first wave was to be the primary attack, while the second wave was to finish whatever tasks remained. The first wave contained the bulk of the weapons to attack capital ships, mainly torpedoes. The aircrews were ordered to select the highest value targets (battleships and aircraft carriers) or, if either were not present, any other high value ships (cruisers and destroyers). Dive bombers were to attack ground targets. Fighters were ordered to strafe and destroy as many parked aircraft as possible to ensure they did not get into the air to counterattack the bombers, especially in the first wave. When the fighters' fuel got low they were to refuel at the aircraft carriers and return to combat. Fighters were to serve CAP duties where needed, especially over US airfields.
Before the attack commenced, two reconnaissance aircraft launched from cruisers were sent to scout over Oahu and report on enemy fleet composition and location. Another four scout planes patrolled the area between the Kido Butai and Niihau, in order to prevent the task force from being caught by a surprise counterattack.
Fleet submarines I-16, I-18, I-20, I-22, and I-24 each embarked a Type A midget submarine for transport to the waters off Oahu. The five I-boats left Kure Naval District on November 25, 1941, coming to 10 nm (19 km) off the mouth of Pearl Harbor and launched their charges, at about 01:00 December 7. At 03:42 Hawaiian Time, the minesweeper USS Condor spotted a midget submarine periscope southwest of the Pearl Harbor entrance buoy and alerted destroyer USS Ward. That midget probably entered Pearl Harbor, but Ward sank another at 06:37 in the first American shots fired in World War II. A midget on the north side of Ford Island missed Curtiss with her first torpedo and missed the attacking Monaghan with her other one before being sunk by Monaghan at 08:43.
A third midget submarine grounded twice, once outside the harbor entrance and again on the east side of Oahu, where it was captured on December 8. Ensign Kazuo Sakamaki swam ashore from her and became the first Japanese prisoner of war. A fourth had been damaged by a depth charge attack and abandoned by its crew before it could fire its torpedoes. A United States Naval Institute analysis of photographs from the attack conducted in 1999 indicated a midget may have successfully fired a torpedo into USS West Virginia. Japanese forces received a radio communications from a midget submarine at 00:41 December 8 claiming damage to one or more large war vessels inside Pearl Harbor. That submarine's final disposition is unknown.
Japanese declaration of war
While the attack ultimately took place before a formal declaration of war by Japan, Admiral Yamamoto originally stipulated the attack should not commence until thirty minutes after Japan had informed the United States he considered the peace negotiations at an end. In this way, the Japanese tried both to uphold the conventions of war as well as achieving surprise. Despite these intentions, the attack had already begun when the 5,000-word notification was delivered. Tokyo transmitted the message to the Japanese embassy (in two blocks), which ultimately took too long transcribing the message to deliver it in time, while U.S. code breakers had already deciphered and translated most of it hours before the Japanese embassy was scheduled to deliver it. While sometimes described as a declaration of war, "this dispatch neither declared war nor severed diplomatic relations". The declaration of war was printed in the front page of Japanese newspapers in the evening edition on December 8.