Confirming Originality

The First Series Digital World Time from SEIKO

Model No. M158-5000 and M158-5009

There are essentially 3 models in the M158 series, two intended for the North American markets (the M158-5009) and one intended for all other markets. The following information will help you determine if a specific example is authentic and original.

The North American Versions

Model No. M158-5009

Under the 5009 sub-model number two watches were produced, one with a stainless steel finish, the other gold plated.

The Stainless Steel M158-5009, on Z-129 bracelet

The Gold Plated M158-5009, on Z-129 bracelet

The Bracelets

Both watches share the same bracelet style and code. The only difference between them is the finish of the case and bracelet, either stainless steel or gold plated.

The bracelet code can be found on the underside of the end links - engraved on the tube that holds the spring bars. It should read Z-129 for all M158-5009's. The style and spacing of the bracelet style designation is different between the stainless steel and gold-plated versions.

The Dial Frames

The Stainless steel dial frame is finished in a black, while the gold-tone version is finished in a gilt/yellow color. Both display the cities as 3-letter abbreviations around the dial.

Both versions share the same dial code: M158-5029T.

The correct Dial Frame for the Stainless Steel M158-5009

The correct Dial Frame for the Gold Plated M158-5009

The International Version

Model No. M158-5000

The international version of the M158 was only produced in stainless steel, included a different bracelet and different dial frame when compared with the North American versions. It was produced under sub-model number 5000.

The Stainless Steel M158-5000, on XAS020 bracelet

The Bracelet

Like most SEIKO watches of the day, the bracelet style code is found on the underside of the end links, on the tube that holds the spring bars. For this version the correct bracelet code is XAS020.

The Dial Frame

The international version of the M158 has a different dial frame when compared with the North American version. Instead of displaying an inner track of time zone offset hours and abbreviated city names, this version omits the offset hour markers and opts for full cities names - presumably for ease of use in non-English speaking markets.

Additionally the QUARTZ LC designation at the bottom left of the dial frame is simplified to read QUARTZ.

The correct dial frame code is: M158-5000T.

The correct dial frame for the M159-5000, Code M158-5000T

Other Considerations

These watches are fairly robust and many good, working examples can be found today. When considering the purchase of a vintage M158, there are a few additional things you should check if possible:

Does the light work? The bottom button on the right side of the case will activate the corner light - which is on the left-side of the dial.
Does the watch work? Be wary of any items sold as is without a battery - often these are bad modules, as a proven good module will command a much higher price, and replacement batteries are easy to find and swap out.
Are there any dead or dim segments in the LCD? This can be checked by pressing the top and the bottom buttons on the right-hand side of the display simultaneously. This will illuminate all segments on the display. Check against the pattern below.