A good point about the chess/trading comparison. As a chess player, I am aware that even though it is a perfect information game, I do not always "see" all the information that is there, and often make careless mistakes or react psychologically rather than playing the board. I also attempt to get my opponent to make those kind of errors too! The lesson is that if we make so many mistakes in a game like chess, we certainly need to work hard to protect ourselves against risk, and against ourselves, in imperfect information games such as investing.