The Kido Butai raid was not an entirely new kind of threat

How much did the Kido Butai raid shock the Royal Navy?

Less as a new form of air threat than as a painful demonstration of British coordination and command failures.

Kido Butai did not present an entirely unfamiliar form of threat to the Royal Navy. Mediterranean operations had already exposed British forces to massed German and Italian air attack. Interwar exercises had also explored multi-carrier cooperation and the long-range strike methods Japan demonstrated. The sharper shock came from Somerville and his staff knowing those concepts yet failing to coordinate their own force as effectively as expected.