The Seiko 5Y31-8A30 is a watch model based on the 5Y31 movement.
Parts List
| 290W91JM01 | crystal |
| 290W91JM | crystal |
| 35MJ5NN1 | crown - crown |
| 0F240BAA3 | case back gasket - case back gasket |
| 0F240BAA | case back gasket |
| WPA50E | band |
| 3AA125F1ANG | others - second hand |
| 12SC39T1 | others - second hand |
| EB0055B01 | others - crown and stem gasket |
| 0351671 | others - winding stem |
| 10T09DGH | others - hour hand |
| 10T09DGM | others - minute hand |