answers: early spring 1941
context: Japan during World War II The Empire of Japan entered World War II by launching a surprise offensive which opened with the attack on Pearl Harbor at 7:48 a.m. Hawaiian Time (18:18 GMT) on December 7, 1941. Over the course of seven hours there were coordinated Japanese attacks on the U.S.-held Philippines, Guam and Wake Island and on the British Empire in Malaya, Singapore, and Hong Kong. The strategic goals of the offensive were to cripple the U.S. Pacific fleet, capture oil fields in the Dutch East Indies, and expand the outer reaches of the Japanese Empire to create a </s> Admiral Isoroku Yamamoto, then commanding Japan's Combined Fleet. He won assent to formal planning and training for an attack from the Imperial Japanese Navy General Staff only after much contention with Naval Headquarters, including a threat to resign his command. Full-scale planning was underway by early spring 1941, primarily by Rear Admiral Ryūnosuke Kusaka, with assistance from Captain Minoru Genda and Yamamoto's Deputy Chief of Staff, Captain Kameto Kuroshima. The planners studied the 1940 British air attack on the Italian fleet at Taranto intensively. Over the next several months, pilots were trained, equipment was adapted, and intelligence was collected. Despite </s> attaché in Washington, D.C... Understanding the inherent dangers of war with the United States, Yamamoto warned his fellow countrymen: "We can run wild for six months or maybe a year, but after that, I have utterly no confidence." The Imperial Japanese Navy made its surprise attack on Pearl Harbor, Oahu, Hawaii Territory, on Sunday morning, December 7, 1941. The Pacific Fleet of the United States Navy and its defending Army Air Forces and Marine air forces sustained significant losses. The primary objective of the attack was to incapacitate the United States long enough for Japan to establish its long-planned Southeast
question: when did japan start planning the attack on pearl harbor