Normally there are 86,400 seconds in a day. Due to a slight change in the earth’s rotation, an extra second may be added to one day during the year. This is called the leap second. Every year the decision is made whether such an adjustment is needed. When the adjustment takes place, the standard time should be corrected by delaying the standard time one second.

To keep your Grand Seiko watch accurate with the world standard time, adjust your watch to a time signal whenever such adjustment is made. According to the information from the observatories all over the world, the standard time is delayed one second simultaneously throughout the world by the Greenwich Royal Observatory.

In the Greenwich Mean Time, an extra second will be added to the one minute between 11:59 p.m. and 0:00 a.m. either on December 31st or on June 30th.

However, the adjustment may not be made in some years. Please check by a newspaper, etc. whether such an adjustment will be made or not.