All through this period US intelligence on the specific characteristics of Japanese weapons and of their training levels was atrocious. Instead of arguing over what they did not know the Navy turned this handicap into an advantage….

…Slowly it dawned on the students - the faculty was giving the Japanese different strengths and weaknesses in each war game!

What were the students to do? Unable to simply learn Japanese strengths and weaknesses before the game they had to play the game in such a way that they could learn them through experience before any decisive engagements took place.

From Toward a History Based Doctrine for Wargaming (full text)