 
 <translate> The important part for answering this question is: Preliminary planning for an attack on Pearl Harbor to protect the move into the "Southern Resource Area" (the Japanese term for the Dutch East Indies and Southeast Asia generally) had begun very early in 1941 under the auspices of Admiral Isoroku Yamamoto, then commanding Japan's Combined Fleet. Final answer: very early in 1941. <ibo> Akụkụ dị mkpa maka ịza ajụjụ a bụ: Atụmatụ mbụ maka ịwakpo Pearl Harbor iji chebe ịkwaga na "Southern Resource Area" (okwu Japanese maka Dutch East Indies na Ndịda Ebe Ọwụwa Anyanwụ Eshia n'ozuzu) amalitela n'oge na-adịghị anya na 1941 n'okpuru nkwado nke Admiral Isoroku Yamamoto, mgbe ahụ na-achịkwa ndị Japan jikọtara ụgbọ mmiri. Azịza ikpeazụ ya bụ: ná mmalite afọ 1941. 