The accuracy of the mechanical watch in use

The accuracy of a mechanical watch varies slightly depending on individual user conditions such as winding state of the mainspring due to movement of the users’ arm, ambient temperature, and posture (direction of the watch). Accordingly, actual accuracy of a watch in use may differ from specifications in the "Grand Seiko Standard."


The target accuracy range of Grand Seiko mechanical watches in use is -1 to +10 seconds per day. To determine accuracy in use, measure loss / gain under normal use conditions for approximately 7 to 10 days and calculate the average loss / gain per day.