Chinook is the strongest 8X8 checkers program around today. Its strength is largely a result of brute-force methods. The program is capable of searching to depths that make it a feared tactician. As with chess, knowledge is the Achilles' heel of the program. However, unlike the chess example, endgame databases go a long way to overcoming this limitation. The program has pre-computed databases that classify all positions with 6 or less pieces on the board as won, lost or drawn (with 7 pieces under construction). The program came second to the human World Champion in the U.S. National Open, winning the right to play a World Championship match against him. Chinook is the first computer program in history to earn the right to play for a human World Championship.