Geography sets a persistent limit on naval plans because distance affects both reaching a theatre and returning from it. For Japan, battlecruisers could combine the information mission with a global-presence role much like the Lexington class for the United States. Their speed and endurance would let them gather information across the Pacific while remaining strong enough to survive contact or reinforce the fleet. The Amagis' 16-inch armament and speed make them the likely visible travellers in this alternate fleet.
Chapter · 33:16-35:49
Pacific geography and the case for Amagi
Pacific distances made fast battlecruisers valuable to a Japan seeking information, global presence, and a visible demonstration of naval capability.