If Pearl Harbor had met a prepared U.S. fleet

What Pacific battle result could most shorten the war?

A prepared U.S. fleet destroying Kido Butai at Pearl Harbor would remove Japan's carrier force at the start of the war.

In this counterfactual, advance warning allows American fighters and bombers to meet the raid while carrier and battleship forces move against Kido Butai. Losing the carrier force in December 1941 would leave Japan little prospect of recovering its historical offensive momentum. The scenario shows how intelligence warning and fleet disposition can matter more than the target list at anchor. The Japanese strike would probably be too committed to cancel by the time its crews discovered an empty anchorage, so everything depends on earlier American warning and preparation.