I was looking at the Kasparov vs Fritz chess game, which was a draw. After reading some background, it seems pretty clear that in a few years the best computer programs will be able to regularly beat the human world chess champion. I then wondered why, when computers are so good at chess, how come they are no way near as good at trading? After all, trading is incredibly simple - there are only a handful of variables (price, time, volume, open interest), and you can only be long, flat, or short. Now I am not very knowledgeable about computers, but the only computer programs that seem to be able to make profits similar to humans are arb programs. Profitable directional programs seem not to exist. Also, the vast majority of system trading seems to be done by humans, using the computers only as aids to system-design, rather than writing a program which then *creates* systems of its own accords. A chess program, once written, can play world class chess. Why can't a trading program, once written, scan the markets itself and then trade profitably? I assume that investment banks and other market players have spent literally billions of dollars trying to write a computer program that can devise profitable trading systems. Given the massively higher resources ploughed into trading computers vs chess computers, why haven't they achieved anywhere near the same success?