Isoroku Yamamoto in the context of "Japanese bombing of Pearl Harbor"

The attack on Pearl Harbor was a surprise military strike by the Empire of Japan on the United States Pacific Fleet at its naval base at Pearl Harbor on Oahu, Hawaii, on December 7, 1941. At the time, the U.S. was a neutral country in World War II. The air raid on Pearl Harbor, which was launched from aircraft carriers, resulted in the U.S. declaring war on Japan the next day. The Japanese military leadership referred to the attack as the Hawaii Operation and Operation AI, and as Operation Z during its planning.

The attack on Pearl Harbor was preceded by months of negotiations between the U.S. and Japan over the future of the Pacific. Japanese demands included that the U.S. end its sanctions against Japan, cease aiding China in the Second Sino-Japanese War, and allow Japan to access the resources of the Dutch East Indies. Japan sent out its naval attack group on November 26, 1941, just prior to receiving the Hull note, which stated the U.S. desire that Japan withdraw from China and French Indochina. Isoroku Yamamoto, commander of the Japanese Combined Fleet, planned the attack as a pre-emptive strike on the Pacific Fleet, based at Pearl Harbor since 1940 in order to prevent it from interfering with Japan's planned actions in Southeast Asia. Yamamoto hoped that the strike would enable Japan to make quick territorial gains and negotiate peace. In addition to Pearl Harbor, over seven hours Japan launched coordinated attacks on the U.S.-held Philippines, Guam, and Wake Island; and on the British Empire in Malaya, Singapore, and Hong Kong.

The Battle of Midway was a major naval battle in the Pacific Theater of World War II that took place on 4–7 June 1942, six months after Japan's attack on Pearl Harbor and one month after the Battle of the Coral Sea. The Japanese Combined Fleet under the command of Isoroku Yamamoto suffered a decisive defeat by the U.S. Pacific Fleet near Midway Atoll, about 1,300 mi (1,100 nmi; 2,100 km) northwest of Oahu. Yamamoto had intended to capture Midway and lure out and destroy the U.S. Pacific Fleet, especially the aircraft carriers which had escaped damage at Pearl Harbor.

Before the battle, Japan desired to extend its Pacific defense perimeter, especially after the Doolittle air raid of Tokyo in April 1942, and to clear the seas for attacks on Midway, Fiji, Samoa, and Hawaii. A related Japanese attack on the Aleutian Islands began one day earlier, on 3 June. The Japanese strike force at Midway, known as the Kidō Butai, was commanded by Chuichi Nagumo. Yamamoto's plan for the operation, which depended on precise timing and coordination, was undermined by its wide dispersal of forces, which left the rest of the fleet unable to support the Kidō Butai effectively.

The Guadalcanal campaign, also known as the Battle of Guadalcanal and codenamed Operation Watchtower by the United States, was an Allied offensive against forces of the Empire of Japan in the Solomon Islands during the Pacific Theater of World War II. It was fought between 7 August 1942 and 9 February 1943, and involved major land and naval battles on and surrounding the island of Guadalcanal. It was the first major Allied land offensive against Japan during the war.

In summer 1942, the Allies decided to mount major offensives in New Guinea and the Solomon Islands with the objectives of defending sea lines to Australia and eventually attacking the major Japanese base at Rabaul on New Britain. The Guadalcanal operation was under the command of Robert L. Ghormley, reporting to Chester W. Nimitz, while the Japanese defense consisted of the Combined Fleet under Isoroku Yamamoto and the Seventeenth Army under Harukishi Hyakutake.