@Zeoic You are both correct. Chess was chosen as an early problem domain for work on first-order logic-based programming. That certainly was considered AI. People really interested in chess later abandoned logic programming in favor of brute-force, highly parallel special purpose hardware. That was not AI.
“Expert systems” (I hate that term) are application area of “Pattern-Directed Inference Systems” (PDIS). Rule-based systems are just one type of PDIS. For example, “Constraint Satisfaction” is another powerful AI technique often used in resource optimization and scheduling systems.