In the aftermath , the Japanese Empire immediately turned its focus to the two remaining rivals for imperial dominance in the Pacific Ocean : Britain and the United States . Satō Tetsutarō , a Japanese Navy admiral and military theorist , speculated that conflict would inevitably arise between Japan and at least one of its two main rivals . To that end , he called for the Japanese Navy to maintain a fleet with at least 70 % as many capital ships as the US Navy . This ratio , Satō theorized , would enable the Imperial Japanese Navy to defeat the US Navy in one major battle in Japanese waters in any eventual conflict . Accordingly , the 1907 Imperial Defence Policy called for the construction of a battle fleet of eight modern battleships , 20 @,@ 000 long tons ( 20 @,@ 321 t ) each , and eight modern armoured cruisers , 18 @,@ 000 long tons ( 18 @,@ 289 t ) each . This was the genesis of the Eight @-@ Eight Fleet Program , the development of a cohesive battle line of sixteen capital ships .