Seikomatic-R 8305: An Early Seiko Automatic

I have here an early Seiko automatic from the 1960s. The first widely recognised Seiko automatic watch was a Gyro Marvel, which I believe was a modular construction with the automatic module added on to a handwinding base, resulting in a somewhat thicker than necessary movement. The Seikomatic, on the other hand, is Seiko’s second automatic watch range, but uses one of Seiko’s first integrated automatic movement.

The Seikomatic series was produced between 1960 until 1967. Multiple movements have powered the Seikomatic series, including the famed 62 movement, which eventually formed the basis for the first automatic GS.

Image taken from

Below is a list of Seiko’s vintage automatic movements taken from a now defunct Japanese website.

Manufacturing dateModel NameabbreviationCAL No.Number of stonesseries
Aug-55Seiko 11 type automatic winding11A17, 21
Jul-59Gyro MarvelGM2901755 series
Apr-60SeikomaticMA603 (6201 B)17, 2062 series
Jun-60Seikomatic 30 stoneMA603 (6201 B)30 
Jul-61SportsmaticSMA66011766 series
May-62SEIKOMATIC SELF DATAMAS394 (6205 B)2462 series
Nov-62Sportsmatic CalendarSMAC7901766 series
Jan-63Seikomatic self data regulation is includedMASK395 (6219 B)3962 series
May-63Sportsmatic FiveSMA56606 (410)2166 series
Jun-63Sportsmatic Calendar 820SAC827625A1776 series
Aug-63Seikomatic slimMAM8303083 series
Feb-64Seikomatic slim dateMAC (MAMD)840 (8305 B)30 
Mar-64Sportsmatic Five DeluxeSMA-5D7606A2576 series
May-64World time62WT6217A, B1762 series
Nov-6466 Sportsmatic Five66SA56619A2166 series
Jun-6576 Sportsmatic Five Deluxe765D7606A2576 series
Seikomatic calendarMAC840 (8305 B)3083 series 
Jul-6583 Matic Week Data83 MW8306A30 
Sep-6583 Seikomatic calendar83 MC8305C / 8325A30, 39 
Feb-6662 Seikomatic Week Data62 MWK6216A3962 series
Nov-6562 Seiko chronometer calendar62 GAC6245A35 
62 Seikomatic Chronometer Week Data62 GAW6246A39  
Jun-6676 Sportsmatic Calendar Deluxe76SCD7605A2376 series
Jul-6662 Grand Seiko Calendar62 GAC6245A3562 series
62 Grand Seiko Weekly Data62 GAW6246A39  
Jan-6751 Matic Week Data51 MW5106A3351 series
Mar-67Bermatic (business bell)40 BW4006A17, 21 and 2740 series
Jun-6751 new five51-55126A2351 series
Aug-6761 New Five DX61-5D6106A2561 series
Sep-6751 New Five DX51-5D5139A2751 series
Feb-6856 Road Matic Week Data 23 Stone56 LMW5606A2356 series
Apr-6856 Loadmatic Week Data-25 Stones2556 series  
Apr-6861 Seikomatic calendar, week date61 MC6105A1761 series
May-68615961596159A2561 series
Sep-6856 Lordmatic calendar56 LMC5605A2356 series
Oct-6856 King Seiko Calendar, Week Data56 KAC, 56 KAW5625A, 26A2556 series
Dec-6870 Automatic Calendar70 AC 1770 series
Apr-6951 Pressmatic Week Data51 PMW5146A27, 3051 series
Jun-6956 King Seiko Chronometer Calendar, Week Data56KCM, 56KWM5625A, 26A2556 series
Aug-7056 Grand Seiko Calendar, Week Data56 GAC, 56 GAW5645A, 46A  
Nov-7052 Loadmatic Special52 LMW5206A2552 series
Mar-7152 King Seiko Chronometer Calendar, Week Data52KCM, 52KWM5245A, 46A  
Jun-7256 King Seiko Vanac56 KAC, 56 KAW5625B, 26B2556 series
Sep-7261 Grand Seiko V. F. A (very fine adjasted)6185, 866185A, 86A2561 series

The Seikomatic-R that I will be presenting today belongs to the 803 series, which was introduced sometime in 1963.

I have always found the general Seikomatic range to be a generally handsome line of watches, being extremely simple but classic looking. I am able to wear my Seikomatic to work and no one would know that the watch is over 50 years old, with the design still standing strong today.

I’m generally not a fan of gold plated watches, especially not of gold plated vintage watches as the plating would tend to have worn off over time.

I do however take an exception when the plating appears to be fairly intact, no doubt helped much by the fact that the crown does not need to be used for winding this automatic watch and good care taken of it by the previous owner(s).

The case diameter measures 34mm across, without the crown, but the thin bezel lends to a huge dial face of 28.5mm. The minimal bezel and white face ensures maximum visibility while keeping things simple, as it should be for a dress watch.

The very sharp hands and bar hour markers are all gold-plated, similar to the case.

The white dial has a faint sunburst pattern to it and is generally unblemished. Pretty remarkable for a over 50 year old timepiece.

The date window at the classic 3 o’clock position is framed within a matching gold plated window.

The acrylic crystal protecting the dial is highly domed, as it is for all watches of that era.

Above, we can see some facets to the lug. The other peeve I have about gold plated watches is that there’s no finishing whatsoever to admire. Whatever contrasting polished and brushed finishings are all protected/hidden by the plating.

Here’s the unsigned crown, which looks a little more worn compared to the case given that the crown would have been handled more frequently to set the time and date.

Above is the case back, with the classic and still in very good condition Dolphin! The early Seiko symbols for water resistance is the Seahorse than the Dolphin (as shown here) before evolving to the Wave motif that everyone is familiar with today. The issue with most of the vintage caseback with the Seahorse or Dolphin logos is that they would generally have been extremely worn through and nearly worn off the caseback. The Wave motif does not have this problem as it’s embossed on the caseback, while the Seahorse and Dolphin motifs are etched on the caseback.

I do not have a picture of the movement, but I believe that my example is driven by the 8305B movement as it has the handwinding capability, but not the seconds hacking ability, which came with the 8305C. The fascinating thing about this movement that I have yet to encounter anywhere else in the Seiko world is that the quickset date works both forward and backwards!

The 830 movement beats at 18,000 bph, and is 28.60mm across while only 3.80mm thick. Contrast this to the evergreen ETA 2824 which is 25.4mm across but 4.6mm thick!

To conclude, after the arrival of this watch, my 56KS no longer takes pride of place as my de-facto go to work watch, as this Seikomatic-R is just as easy to wear while adding a touch of classy gold to it. It does lack the distinctive Grammer of Design case, but it trades it for the classic vintage Seiko design.

History of Seikomatic:

List of Seiko Vintage Movement (any spelling mistakes are mine as the original is in Japanese):

Seiko 830 movement:

Breakdown of the 830 movement:


One thought on “Seikomatic-R 8305: An Early Seiko Automatic

  1. I think you do, in fact, have an 8305C movement in your watch. It doesn’t hack, but can hand wind, which is an upgrade from the previous 8305 movements. I’ve got an 8305-8030 with the one-piece case that has the same dial and hands as yours, but in silver. It’s a tidy little watch, classy and understated – one of my current favorites.
    Not my blog, but I did get some very good info from this really good tear-down article over here:

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