How Germany, Italy, and Japan posed different maritime risks

Japan required Britain to sustain a fleet and its infrastructure on the other side of the world, while Italy threatened the Mediterranean route and could force trade around Africa. Germany looked weaker in conventional fleet terms during the early 1930s, but it was the opponent best placed to wage a direct submarine campaign against Atlantic trade. Japanese submarines would face extreme distances and chokepoints, while Italy could be contained between Gibraltar and Alexandria. German access to Norwegian and French bases later transformed the convoy problem, but planners in the early 1930s could not assume those conquests. Each opponent demanded a different mix of fleet, base, and escort investment.