Produced from 1993 till 1995 this quartz has it all. However, almost nothing is known about this JDM watch, it cannot even be found in any of the likely catalogues when looking at the serial number! (And VintageseikoNL has almost all of them!) Truly a mystery watch then that must have been produced for a very short time indeed. Looking at the catalogues the caliber 6M15 was present only in the years cited. Fortunately a manual is available here. This is a serious watch with all the time dedicated functions you have and have not imagined. Leap year, anyone?

The SEIKO Quartz Watch Cal. 6M15 is an analogue watch featuring calendar, world time, alarm and stopwatch functions.

■ TIME

Hour, minute and second hands and a small 24-hour hand.

■ CALENDAR

Date is displayed in numerals and month is indicated by the hour and minute hands. The second hand indicates the number of years that have passed since the last leap year. The calendar automatically adjusts for odd and even months including February of leap years up to 2099.

■ WORLD TIME

The time of 22 time zones throughout the world is displayed. Daylight saving time (DST) and standard time (STD) of those time zones can also be displayed as required using the "Yankee"

simply by turning the crown.

• Time transfer a convenient way of using the WORLD TIME mode

The time displayed in the TIME mode can easily be replaced with that of any time zone in the WORLD TIME mode. This function is very useful when you travel abroad. The time of the city you visit can be shown on the watch without resetting the hands.

■ ALARM

The alarm can be set to ring on the basis of the time of a desired time zone. It can be set on a 24-hour basis in minutes and rings once a day.

■ STOPWATCH

The stopwatch can measure up to 23 hours, 59 minutes and 59 seconds. It measures in 1/10 second increments for the first hour, and in second increments thereafter. Split time measurement is possible.

■ BATTERY LIFE INDICATOR

The second hand moves at two-second intervals when the battery needs to be replaced.

The complications of this watch are displayed on the sub dial at 6 o’ clock, activated by turning the crown - clockwise or counter clockwise. In random order you can do the following:

In Time mode: show regular time, the minutes can be set when the crown is pulled and the 10 o’clock pusher is depressed, the seconds hand automatically hacks to zero so this can be set precisely. The 8 o’clock pusher is used to set the hours.

In Chrono mode: turn the crown counter clockwise and all three hands set to zero (if not read Reset chrono after battery change), when started by the 10 o’clock pusher, the seconds hand "sweeps" back and forth between 12 and 1 o clock, showing 1/10 second intervals as displayed on the dial, hour and minute hand indicate seconds and minutes.

In Month/date mode: all three hands point the month of the year, shown on edge of dial. This may seem silly but in fact it is essential for the perpetual calender which will accurately keep track of say the month of February. Finally, in Timer mode the hands can be set to countdown to zero.

Complications that are less used and often forgotten are the Set alarm mode, the hands can be set to the alarm time and when the Yankee is on the Alarm on mode the alarm is active, to be deactivated by any of the pusher buttons.

Reset chrono is important after battery change (complete circuit reset). Because if the chrono does not reset to 12 o’clock it is probably after a battery change. The chrono needs a reset like this:

Turn the crown to indicate Chrono on the sub dial

Pull out the crown to first click

Press both pushbuttons at the same time for two seconds; the hour an minute hands start moving counterclockwise and clockwise respectively. The seconds hand moves back and forth.

Press button A or B to stop the hands

Press button A to select the hand to be adjusted, it moves back and forth when selected. It is on a hair trigger so watch it, you can end up with the date selected before you know it (which will advance one day and back again to indicate selection)

Press button B to reset the selected hand to 12 o'clock, the date would reset to 1 (hands and date move quickly when B is kept depressed).

When finished push the crown back.