The base stock policy for a serial two echelon supply chain with independent but non-stationary (time dependent) demand is discussed. Each stage incurs certain holding cost and shortage cost at the end of each period. The system is examined under both centralized and decentralized control scheme. In decentralized frame, two different game formulations are considered. The first one is the repeated game. In each period a one-period game is played and for T- period finite horizon, these one-period games are played T times. Each one-period game has a unique Nash equilibrium, however...