Japanese attrition and ambush before decisive battle

Japanese carrier doctrine assumed that the United States would advance across the Pacific or Britain would approach from the south. Interception and attrition operations would attack that advance with submarines, destroyer and cruiser torpedoes, and aircraft. Carriers and capital ships were targets well before the enemy reached Japan. A more concentrated ambush could then strike a separated task group, preferably at night or dawn. Only after this weakening would much or all of the Japanese fleet seek a decisive battle against an enemy reduced toward parity or inferiority. The sequence depended on the opponent continuing its advance despite losses. The Imperial Defence Policy and Imperial Defence Doctrine supplied the wider framework, although their interpretations did not always agree.