Seiko 5Y23A

The Seiko 5Y23A is a vintage quartz movement manufactured in Japan. It measures 25.4mm in diameter and 2.7mm in height, uses an SR920SW battery, and contains 371 or 370 jewels. The movement includes a day-date calendar complication, distinguishing it from other calibers in the 5Y family such as the 5Y22A, 5Y30A, 5Y31A, 5Y32A, and 5Y39A. Technical documentation confirms production at least since June 1988. The movement appeared in Seiko watches with case number 5Y23-7089.