What is the fine-grained topic of the following text: Three Long Time Control ChallengesAs a serious challenge for the new Houdini 3, last month three long matches between the Houdini 3 Beta version and other top engines (Houdini 2.0c, Stockfish 2.3.1 and Komodo 5) were played. Only return the topic.
Long matches between Houdini 3 Beta version and other top chess engines