I always thought that Varys and Littlefinger play the game very well but as far as understanding exactly what the game is, as well as understanding many other things to a larger extent then anyone else around him its Tyrion. Tyrion is a vehicle that Martin uses to express the wonders of reading and learning, as well as a warning about whoring and drinking. I think Tyrion is Martin in the story. A lot of people think Varys is. I think its Tyrion.