Seiko 5

Seiko 5 or Seiko Five is a series of low-cost watches manufactured by the Japanese watch company Seiko . Although they are official Seiko watches, the manufacturer does not present them on its website. The identification of these watches is easy: they have on their dial a badge “5” just below the inscription Seiko.

This range of watches was born in the 1970s from a simple idea that gave it its name: to provide the five essential functions expected of a timepiece. Thus, the Seiko 5:

  1. Give the time;
  2. Display the date;
  3. Are waterproof;
  4. Are anti-shock;
  5. Have a self-winding mechanism.

The current form of these watches dates from the mid-1990s, after the “quartz revolution”. The Seiko 5 are of Japanese design and are currently mainly produced in Southeast Asia ( Singapore , Malaysia ), and more rarely in Japan .

The 5 functions of a watch Seiko 5

Time display

These watches display the time in analog form: three hands make revolutions on a dial to indicate the hour, minutes and seconds.

Date display

These watches display in a ticket office, or sometimes two separate windows, the day of the week and the date. The day of the week can be displayed in the form of the first three letters of the day in a language (mostly in English or Spanish) or Roman numerals (from I to VII). The day of the month is displayed as a number between 1 and 31.


The waterproofness of these watches varies from one model to another and extends from “waterproof” to “water resistant 50/100/200 meters “. This sealing is ensured by screwed bottom and crown. The level of sealing is the main factor justifying the price differences between the different models.


To resist scratches and scratches, these watches are equipped with a hardened mineral glass produced by Seiko, the Hardlex, and benefit from a patented anti-shock system named Diashock. However, fully mechanical movements remain quite sensitive to violent shocks, repairs are costly, and this type of basic Seiko movement seems less protected against shock than some other more sophisticated but more expensive movements . Required] .

Automatic movement

These watches go back on their own when they are worn by a mechanism called automatic winding . The high frequency of oscillation (21,600 beats / hour) allows the second hand to move smoothly (6 movements per second). The average variations observed for these timepieces are of the order of 3 to 30 seconds per day (variation which may be positive as well as negative), far from the precision of a very cheap quartz watch or movements High-quality mechanical equipments for luxury watches. The precision announced by Seiko is of the order of -15 to +25 seconds / day. But, with good adjustments, it is possible to obtain a much better precision.

The movement Seiko 7s26


The Seiko 7s26 movement, a rustic mechanism

The Seiko 5 watches are mostly equipped with a 7S26 type movement. This caliber, fairly hardy, is characterized by:

  • 21 jewels ;
  • Frequency of 21,600 bph;
  • Lifting angle of 53 °;
  • Reassembly thanks to the bidirectional movements of the rotor;
  • No manual winding ( it is therefore impossible to reassemble the watch with the crown );
  • No second stop ( when the time is set, the seconds hand will continue to rotate );
  • A power reserve ( autonomy of the watch without winding ) of the order of 40 hours. The manufacturer recommends wearing the watch around 8 hours a day to prevent it from stopping;
  • Rapid change of date around midnight ( largely made up of plastic parts );
  • Noise: Like any mechanical watch in operation, the 7S26 caliber emits a discreet “tic-tac” at the same rate as the movement of the second hand. Moreover, the rotation of the oscillating mass (or rotor) which allows the winding of the watch is quite noisy and is heard when the wearer agitates the wrist.

The Seiko 5 in the “superior” range are equipped with the 7S36 23-ruby movement, very similar to the previous 7S26, the addition of 2 additional rubies is more of the marketing – mention on the dial – than The functional improvement of the movement.

The latest models come with the movement 4r36 or 4r37 with 24 jewels, which introduce the possibility of manual winding and a stop second.

Brief history

Source 2 , 3 :

At the time of their creation, in the 1970s, the first Seiko 5s were equipped with an automatic 6309 movement, then 7009 in 1978, replaced in 1996 by the 7S26A then in 2006 by the 7S26B and in 2011 by the 7S26C. The 7S26B and 7S26C are minor changes to their predecessor: the only differences are in the parts used to fix the spiral spring to the racquet (“Etachron” regulator) and, for the 7S26C, 4 Screws instead of 3. In a more general way, the 7S26 is an improvement of the 7009 (heavier oscillating weight to improve automatic winding among others), of which it largely takes the base (platinum almost identical). Like him, the pieces of the piece are stamped,

The movement 7S26, a manufacturing movement

The movement 7S26 is a movement made by Seiko himself, which allows him to run for the status, appreciated by connoisseurs, movement ( en ) in house or ( fr ) of manufacture . However :

  • Few manufacturing operations are actually done by hand (the same is true of Swiss industrial manufacturers such as Rolex or Omega – as regards its movement 8500)
  • Although it is true that Seiko does not broadcast this movement on the watch market, the 7S26 nevertheless equips the watches of subsidiaries of the Seiko Instruments Inc. (SII) group such as Alba or J.Springs, watches in which the caliber 7S26 is then renamed Y675 / Y676.

The different models


The variants of the Seiko 5 are extremely numerous, it is nevertheless possible to distribute the Seiko 5 watches in three main categories:

  • Military models equipped with nylon bracelets, Military models are also characterized by the great legibility of their dials, day and night;
  • Models without a particular denomination mostly equipped with metal bracelets (usually in simple folded sheet), this category includes the female models of more modest size;
  • The Sports and Diver’s models (underwater diver in French) with reinforced waterproofing and equipped with metal or plastic bracelets; These models are recognizable by their voluminous bezel surrounding the glass (sports models have decorative fixed glasses, while Diver’s models have unidirectionally rotating bezels).

Possible variants

If we go into details, it is impossible to list precisely the number of variants existing for this watch so much their number is important. The differences are sometimes minimal and make any choice Cornelian. For example, there are identical models with the exception of one color (for example, the color of the date window or the end of the second hand that can be painted red). Nonetheless, it is possible to cite, without claiming to be exhaustive, the components which vary most often:

  • The dial: color and pattern of the background; Color, size and location of wickets; Presence, shape and colors of indexes;
  • The needles ranging from massive rectangular needles to flat ends to rather slender needles with pointed ends or even raised by an arrow;
  • The case: size, shape, position of the movement in the case (crown at 3 or 4 hours 4 ); Appearance of the case (brushed, shiny …); Presence of an outside or non-rotating bezel, rotating or fixed; Shape and size of the horns holding the bracelet or the spacing of these horns which determine the width of the bracelet;
  • The bottom: transparent showing the more classic opaque metallic mechanism or background;
  • The bracelet: fabric, metal or plastic; Models with leather bracelet exist but they are much rarer because of their higher price can double the overall price of the watch.

Purchase and Counterfeiting


Given the low price of Seiko 5 watches, there are few counterfeits in circulation. Moreover, Seiko has set up a fairly original parade to limit counterfeiting: some Seiko 5 are equipped with a transparent background that reveals the mechanism, which facilitates the identification of coarse copies.

Repair and Maintenance

The maintenance recommended by Seiko is similar to that of other brands selling automatic watches and consists of a regular review.

If, after a simple maintenance, a repair of the movement is necessary, then often it is advisable to opt for the replacement of the complete movement with a new one.

However, the availability of spare parts is total, and professional watchmakers are able to order spare parts, as the “classic” movements architecture requires no specific know-how or equipment, making even the Old models, Seiko 5 watches perfectly repairable unlike automatic Swatch , entry-level Swatch Group , One can note, regarding the durability and availability of parts of this movement, that the main elements the component are common with Many other movements built by Seiko, some positioning more “upscale”: the recent movement 6R15 that equips the watches of the middle range for example (and which disposes,Apart from the possibility of being manually wound up, of the stop-seconds device facilitating the precise timing of the watch), is actually built on a 7S26 basis with which it shares most of its components.


  1. ↑ illustration: model Seiko 5 with the reference SNK801K1
  2. ↑ The Brazilian Adriano Ramos Passarelli has reconstructed in detail the evolutions over time of the movements of the series 70xx from which the caliber 7s26 is derived: ( pt ) Html  [ archive ]
  3. ↑ Seiko 7S26 on Watch Wiki  [ archive ]
  4. ↑ Specifically crown 3 hours 46 minutes . This position, which may seem surprising, can be explained: it corresponds to an integer number of days apart between the crown / day set of the month and the window placed at 3:00 am for a horizontal reading of the date. Thus, whether the crown is positioned at 3 h or 3 h 46, the watch is equipped with the same movement.

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