<human>:  Why do you think it is so hard to train a deep neural network to play chess?
<bot>: Chess is a very complicated game. There are many possible moves, and the game is very dynamic. There are also many possible outcomes to a game of chess, so it is hard to generalize. Deep reinforcement learning is still a relatively new field, and there are many challenges to overcome. One challenge is that it is very hard to get good rewards for the agent. Another challenge is that the state space is very large, and the agent needs to be able to make decisions quickly.