This watch is a mechanical watch that runs by a mainspring.
Before using the watch, turn the crown by hand about 20 times to wind up the mainspring of the watch.
While the loss / gain of a quartz watch is shown by the monthly or yearly rate, the loss / gain of a mechanical watch is shown by the daily rate (loss/gain per one day).
The loss / gain of a mechanical watch changes delicately day by day, depending on various environment or conditions in which the watch is used (such as temperatures, the amount of time the watch has been worn, the amount of arm movement, and the amount that the mainspring is wound up).
A mechanical watch may lose / gain time when it is affected by strong magnetism. If the parts of the watch become magnetized, the watch needs repair including demagnetizing. In this case, consult the retailer from whom the watch was purchased.