After the end of WW2, US military intelligence interviewed captured Japanese Generals, and asked them how they thought they could defeat the United States. A number of them explained that they saw the American newsreel from 1940-1941 showing the US Amy practicing with wooden guns. Their overall impression was that it will be a “piece of cake”, as a “real military” would never use fake weapons. Pictures send a giant message.
American newsreel from 1940-1941 showing the US Amy practicing with wooden guns
Then the Japanese started using Wooden Bullets