Global trade routes define the cruiser battlespace

Royal Navy planning for war with Japan spread cruisers across a first line in the Pacific and supporting stations farther behind it. The plan included the Gilbert Islands, Rabaul, Hong Kong, Australian bases, and Esquimalt because no single concentration could cover the ocean's dispersed trade routes. Ships initially assigned to Hong Kong might move forward, while cruisers from Trincomalee or Australia could reinforce the theater. The same geography supported both protection of Commonwealth shipping and attacks on Japanese maritime supply. In a separate war plan, the Navy intended to exclude Japanese access to the Indian Ocean, isolate Germany from overseas trade, and close the Mediterranean against Italy. Rerouting traffic around Africa made large, economical merchant ships especially important because every voyage became longer.