Britain, America, and estimating Japan

Was British and American underestimation of Japan mainly a postwar stereotype, and who pushed that view?

Accurate assessments existed, but decision-makers failed to listen to the people producing them.

The answer rejects the idea that Britain and the United States simply lacked accurate assessments of Japan. The Royal Navy had substantial documentation and made a close estimate of Yamato and Musashi's gun size from a photograph. The institutional failure came when leaders ignored specialists who had produced good estimates.