Why is it that decades of research was required to construct

Why is it that decades of research was required to construct a computer chess program that plays at the grand master level? Although computer technology has been in existance since the 1940s, a chess program at the grand master level was not accomplished until the 1990s? Many people thought it to be impossible.

Solution

Chess is a very complicated game. A human brain think about 100 moves in advance. A grand master is supposed to think a 1000 moves in advance after analysing each move and its counter moves. A chess program by computer can think and analyse 1 million moves in a minute. To have such a technology it required a computer programmer to be a chess player of great understanding. Hence it took such a long time to have sucha computer program at the grand master level