Seiko 6347-5000; Automatic MoonphaseModel: Seiko 6347 5000 Automatic Moonphase Year: October 1986 Features: The Complication. Strangely, this is the only automatic Moonphase Seiko has ever produced. It was released in 1986 and quickly disappeared from Seikos line up, making this a difficult watch to track down. I know it seems like an absolute impossibility for Seiko not to have produced another automatic Moonphase in 38 years but they havent. Theyve made lots of Quartz Moonphases and