The Seiko 7017A is a watch movement that was used during the period from 1953 to 1955. It features a patented double-excenter winding system with jewelled rollers and a jewel-bearing rotor. The movement incorporates an intermediate wheel between the minute pinion and the rest of the train, enabling a large balance and low profile without compromising durability. This design also allows for the placement of the seconds wheel in either the center or for a sub-second, depending on the model, without requiring additional modifications. Early samples of the movement may have a hidden balance cock and may be partially or fully pink gold plated, while late samples feature a new rotor lock and ring balance. The movement functions include automatic winding and a sweep second hand.