In the early 1960's sports timing was dominated by mechanical stop watches. Seiko has produced a large range of mechanical stopwatches at various price points, but there were a series of three models that are a step above the others and they have an interesting and highly influential story behind them. These models are known as the 89ST series and were listed as Luxury Stopwatches in the Seiko domestic watch catalogs.
The three models in the 89ST series are differentiated by their functionality, with capabilities to measure to 1/5th, 1/10th or 1/100th of a second.
The 89ST 010 can measure up to 30 minutes duration in divisions of 1/5th of a second and has a split second function. The stopwatch movement operates at 5Hz (18,000 bph). A sub-dial at 12 o’clock indicates the elapsed minutes and the outer dial markings are divided into 1/5th of a second increments. One rotation of the seconds hands around the dial, indicates an elapsed time of sixty seconds. The stopwatch has three pushers and is operated as follows. To start the watch the right pusher is depressed, the split second function is activated by pressing the left button during operation. When the left pusher is activated, one of the seconds hands is stopped allowing the elapsed time to be recorded, while the other seconds hand continues allowing the timekeeping to be maintained. Once the split time has been noted the left button can be pressed again allowing the paused second hand to catch up with the moving hand. To stop the chronograph the right button is depressed. To reset the hands the crown is depressed. The stopwatch is wound via the central crown.
The 89ST 020 can measure up to 15 minutes in divisions of 1/10th of a second and it has a split second function. The stopwatch movement operates at 10Hz (36,000 bph). A sub-dial at 12 o’clock indicates the elapsed minutes and the outer dial markings are divided into 1/10th of a second increments. One rotation of the seconds hands around the dial indicates an elapsed time of thirty seconds. The first 30 seconds are denoted by the white numerals in black squares around the dial, while the next 30 seconds in the minute are displayed with the inner markings of black text on a white background. To determine if the first or second 30 second markings should be used the hand on the 15 minute sub-dial will point to either a black or white section. The operation of the stopwatch is the same as the 89ST 010 with the right pusher operating start and stop functions, the left pusher to split and return the seconds hand and the crown to wind and reset the stopwatch.
The 89ST 030 can measure up to 10 minutes in divisions of 1/100th second. The stopwatch movement operates at 100Hz (360,000 bph). A sub-dial at 12 o’clock indicates the seconds and the inner central dial will show the minutes elapsed. One rotation of the seconds hand around the dial indicates an elapsed time of three seconds. The right pusher starts and stops the watch and the crown will wind and reset the watch.
All three models in the 89ST series were released in June 1963 and make their last appearance in the 1977 Vol.1 Seiko JDM watch catalog. They each have 15 jewel movements measuring 49.6mm in diameter with a thickness of 10.7mm. The exterior of the watch (case, hands, crystal, dial) could be serviced by authorised dealers but the service of the movement could only conducted by returning the watch to Seiko. 
The history behind the development of these stopwatches is interesting and is directly tied to the awarding of Seiko the role of official timer for the 1964 Tokyo Olympics.
In the spring of 1960 it was announced that Tokyo would host the 1964 Olympics, the first time the Games were to be held in Asia. As soon as this announcement was made Shoji Hattori (Seiko Corp. President 1946-74) decided that Seiko should handle the official timing duties for the Tokyo Olympics. Hattori-san sent a telegram to Saburou Inoue the Watch Design Section Manager at Daini-Seikosha, who was travelling in Switzerland for business, instructing him to visit the Rome Olympics to observe how the timekeeping was conducted. Inoue-san did not go to Rome but instead tasked one of his staff to attend. Upon returning to Japan Inoue-san was visited by Hattori-san who told him that he intended for Seiko to be the timer of the Tokyo Olympics. Inoue-san stated that this would not be possible as the games were just four years away and Seiko would have to build complete timing systems from scratch as they did not currently have suitable experience in sports timing. Hattori-san did not accept this response and over the next few weeks it became clear that he could not be swayed in his plans.
To determine what would be required and produce the systems necessary for the Games they examined the various timing methods and equipment used for international events at that time. All timing was conducted by human operators and as there was commonly slight variations between the recorded times it was common practice to use multiple operators, and then average the results, to provide the best accuracy. It was thought that the slight variations between recorded times was due to the reflexes and skills of the operators, so many sporting bodies had processes to certify operators who would conduct official timekeeping duties. 
The lack of history and preconceptions of sports timing from Seiko allowed them to view the issues facing timekeepers from a different perspective than established manufacturers. Inoue and his team took multiple examples of the standard stopwatches and designed a machine to mechanically operate them at the same time, eliminating the human element from the timing process. They found that even when the stopwatches were started and stopped at exactly the same time they would commonly show different results, indicating that it was not the operators but the watches themselves that were in part to blame for timing differences.
After various experiments and examining the design of the watches the team at Daini determined the differences in timing were caused by the balance wheel location being at different points when the watch was operated. This meant that when started the balance could interact with the pallet fork almost immediately or almost a full beat later. To resolve this issue the team attached a heart shaped cam to the balance staff ensuring that the balance was always started and stopped consistently in the optimal position.  You can see the heart shaped cam located on the balance staff in the images below.  
The heart cam was proven to significantly increase the accuracy and consistency of the stopwatches and the design was eventually patented in Japan, the US and the UK.
To also improve consistency the balance was fitted to a full bridge, supporting it from both sides, in a design that Daini also used for their entrants into the Neuchâtel Chronometer competitions. The dial was fixed to the movement with a pair of screws through the face ensuring the marker alignment.  The hands were also bent down to place them as close as possible to the dial surface to eliminate any potential parallax error when reading the time. Another cam was also added ensuring that the hands always aligned with the markers when the watch was stopped.
In September 1962 the Olympic Technical Committee met in Belgrade to determine the official timer for the Tokyo Olympics. Seiko sent Masatoshi Tohyama, the Research Section Manager, to the meeting to demonstrate Seiko’s offerings and put forward their case to be considered for the Official Timer role. Tohyama-san took with him six examples of both the 1/5th and 1/10th second 89ST stopwatches. During the trip to Belgrade his plane made a stop over at Zagreb and the case containing the 89ST watches was offloaded. Luckily when returning to his seat after the stop, Tohyama-san noticed these were missing and eventually the case was located on the tarmac before continuing the last leg of the journey.
At the meeting in Belgrade the stopwatches were tested by members of the Olympic Technical committee, Mr Donald Pain, Honorary Secretary International Association of Athletics Federation (IAAF), and Adriaan Paulen, President of the Dutch Athletics Federation, who would later become IAAF president in 1976. Mr Paulen tested the stopwatches by selecting a pair of watches and operating them simultaneously in each hand. He tested the watches for a few seconds, then a few minutes and finally near an hour of operation. When he stopped the watches they matched perfectly for the first two tests and were only showing a difference of 1/10th of a second over the longest duration.  Paulen, who had a strong technical background, was very surprised by the performance of the watches and asked for an explanation as to how this had been achieved. At the conclusion of the meeting the preliminary decision to appoint Seiko as the official timekeeper was made. The technical committee stated that “We are not assigning official timekeeping to a Japanese manufacturer because the Olympics will be held in Tokyo, but because these are actual functional stopwatches, backed up with solid theory.” 
After the preliminary decision to appoint Seiko as the official timekeeper for the Tokyo Olympics the watches were sent to the National Physical Laboratory in England for certification as Olympic timekeeping equipment.  The official notification that Seiko was the timekeeper for the Games was only received in May 1963, with the competition starting just 17 months later in October 1964. 
In addition to the 89ST stopwatches Seiko had to develop many other timing and display devices for the Olympics, so the teams across the multiple companies were pushed to the limits. The physical layout of the 89ST models was the responsibility of legendary Seiko designer Taro Tanaka  who was also strongly assisted by Masayoshi Aoki from Daini-Seikosha’s design department. The initial design of the 1/10th sec. 89ST model had a more visually cluttered layout with small text, different sub-dial design, and a solid dark outer ring. This original prototype design can be seen pictured in a report detailing Seiko being selected as the preliminary preferred Games timer in a 1962 Japanese trade journal.  The final design of the dial is much cleaner and easier to read. Unfortunately due to the very tight schedule a number of ideas that Tanaka-san and Aoki-san had for the 89ST series were unable to be implemented before the Tokyo Games.
During the 1964 Tokyo Olympics the 89ST models were utilized for timing on numerous sports and a total of 752 examples were used. The choice to use the 1/5th, 1/10th or 1/100th seconds models was dependant upon the type of sport being timed and the precision required.
The table below shows the quantities of 89ST models that were used per sport during the 1964 Tokyo Olympics.
|1964 Tokyo Olympics||1/5th sec.||1/10th sec.||1/100th sec.||Total|
The 89ST models were commonly used in the publicity from Seiko when promoting their official timing status for the Olympics. The inside cover of the 1964 Tokyo Olympics Official Souvenir has an advertisement from Seiko showing a 89ST 020. This advert makes the statement that the same precise technology used to create the Olympic timers is also applied to Seiko watches. The 89ST 020 model can also be seen in a general Seiko advert from the International Edition of Life magazine released during the same period.
Seiko also featured the 89ST models in their publicity material to international sporting associations where they described the devices that were going to be used for the Tokyo Olympics. The 89ST can be seen on the cover of the brochure Sports Timers for the XVIII Olympic Games as well as the pages for track and shooting events.
After their use at the 1964 Olympics the 89ST models continued to be sold essentially unchanged to the public all the way up until 1977. During this time Seiko was selected as the official timer for the 1966 Asian Games in Thailand, where they utilized the same timing systems as used in Tokyo including the 89ST. While the mechanical timers operated correctly the excessive heat in Bangkok forced Seiko to implement additional cooling for the electronic timers.[16a] Seiko was also the official timer for the 1967 Universiade held in Tokyo and utilised many of the Olympic facilities. At this event the 89ST 1/5th sec. models were used for the athletics, fencing, basketball, gymnastics and judo events, and the 89ST 1/10th sec. units were used for athletics and swimming. In a number of events the mechanical units were used as backups to electronic timing systems.[16b] The 89ST models were pictured in a brochure for the Universiade produced by Seiko as the official timekeeper for the event.
By the time of the 1972 Sapporo Winter Olympics sports timing had mainly changed to quartz based electronic systems. Consequently the mechanical stopwatches were mainly used as a third level of timing behind two redundant electronic systems.  In preparation for the 1972 Winter Games the Sapporo Winter Sports Week event was held in February 1971 where the same sports were conducted. This was a trial event for both the timing systems and the general logistics of the upcoming Games. During this week 140 stopwatches were used for the following sporting events in Sapporo and this allocation was closely replicated the following year for the Games.
|1971 Sapporo Winter Sports Week||1/5th sec.||1/10th sec.||1/100th sec.|
|Alpine (Downhill, Slalom, Giant Slalom)||45|
Seiko produced a promotional package for press and sporting associations explaining the different timing systems that would be used at the Sapporo Games. As part of this package they included images of the stopwatches and details of which events would utilize them.
When the Sapporo Winter Games occured in 1972 there was a strong public backlash against the commercialisation of the Olympics that was seen to be corrupting the pure athletic performance of the athletes. Seiko made the decision that they would remove all branding from the public facing clocks and timing systems that were in use during the Games. This happened in all locations with the exception of the main scoreboard in the speed skating rink, as construction had already begun and it was not feasible to alter. The stopwatches retained their Seiko branding as they were operated by officials and were not seen by the public.
The Sapporo Games were the last Olympics where mechanical stopwatches were officially used as portable electronic systems had completely replaced them at an international sporting level by 1976. While the 89ST continued production and sale until 1977, the advances introduced in the design for the 1972 Sapporo Games were never implemented in a production model for public sale. These stopwatches are extremely rare as very few units were produced, unfortunately even Taro Tanaka does not have an example of these models in his personal collection. 
While Seiko did not display their logo prominently during the Sapporo Olympics they still promoted their involvement in numerous advertising placements in various publications. An example of this advertising can be seen in the inside cover of The Mainichi Graphic Special Sapporo Edition.  As you can see from the advertising, the focus was on electronic devices, but the mechanical 89ST stopwatch was still prominently displayed.
The Sapporo Olympics 89ST model is also featured on the front and rear cover of the 2014 book Lectures on Mechanical Watch from Shoichiro Komaki. Komaki-san was General Manager of Research and Development at Daini-Seikosha (now Seiko Instrument Inc.) and worked for the company from 1958 till 1987. This book covers a range of topics on watchmaking and has a short section discussing the 89ST models that were developed for the Sapporo Olympics. 
After being released in June 1963 the 89ST models appear in the first 1966 Seiko catalog. They also appear in the second catalog from 1967 but only the 010 and 020 models are shown. In the 1968 catalog the 010, 020 and 030 models are priced at 24,000円, 25,000円 and 32,000円 respectively. In the 1973 Volume 2 catalog the pricing for each model was increased to 30,000円, 32,000円 and 40,000円. Prices for these models was again increased a year later, in the 1974 Volume 2 catalog, to 34,000円, 36,000円 and 46,000円.
In the 1975 Volume 2 Watch Catalog the pricing remained the same but the model names were changed from the series unique number format to the new format of three alpha character and three numeric characters. The new model names were TYB010, TYB020 and TYB030. Around mid 1976 the pricing was changed for the 89ST models. In the 1976 Volume 1 catalog the prices remain the same, but I have seen an example of the catalog where the prices were updated by hand to 40,000円, 43,000円 and 50,000円 for the three models respectively.. This pricing can be seen officially in the following catalogs. All three models appear for the last time in the 1977 Volume 1 Watch catalog.
The watches were provided in a black case with a hinged lid and Seiko printed in silver on the top surface. The inside of the case was lined with either a red or blue material and the bottom half of the case was lined with a black velvet section containing an indent for the watch. The inner lid section of the box includes a pocket to store the manual and warranty card. I have seen all models offered for sale in both the red and blue boxes, so I believe that the color changed during production and was not specific to a particular model. The red lined boxes seem to be the more prevalent configuration.
One common Seiko accessory that is often seen fitted to 89ST models is a protective rubber case. The calibre number is marked on the inner rear surface, and the three pusher holes at the top of the case makes it easy to identify which stopwatch series this is designed for. This rubber case can allow moisture to collect around the inner edge, so it is not unusual to see 89ST examples where the nickel plating has been damaged and flaked off around the outer edge of the dial or around the pushers.
The calibre numbers for the different 89ST series models are a little unusual compared to normal Seiko watches. In the 1976 and 1977 catalogs the movement number is referred to as 8909 for all of the models. If you look at the case backs of the stopwatches the 1/5th second model is shown as 8912-5000, the 1/10th second is 8922-5000 and the 1/100th second 8941-5000.
If you look at the movements the markings varies depending upon the year of production. Up until 1967 the movements appear to only be marked as 890, after 1967 the movements seem to be marked with a character indicating the type. The 1/5th second is an 890A, the 1/10th second an 890B and the 100th second the 890C. This is also how the movements are differentiated in the calibre reference table in the 1976 Seiko Watch Catalog. All movements are marked with individual serial numbers and these do not match the serial numbers stamped on the case backs.
The 890A and 890B movements look very similar to each other but the 890C (1/100th second) model is easily identified by the much smaller balance wheel. If you look at the hairspring on the 890C you will note that this is much thicker than normally found on watches. This is obviously due to the extremely high beat rate of 360,000 bph that the movement operates and the speed and forces that the balance must rotate at. Another unique feature on the 890C is a small lever that gives the balance a kick when it is started, this is needed because of the stiffness of the hairspring requires more force to ensure the balance is started with the same repeatable action.
The finish of the movements also differs depending upon the production years with the earlier models having more elaborate decoration.
Due to the long production run all of these models are relatively easy to find, with the 89ST 030 (1/100th sec.) being a little less common.
The mechanical stopwatch had been replaced by digital quartz based models by the mid 70's for professional timekeeping, and by the early 1980's this technology had already filtered down to the general public.
The 89ST series are the most interesting mechanical stopwatches from Seiko. With the strong history behind the models, split seconds or 360,000 bph functionality, and the Olympic connections, the 89ST series are an interesting addition to anyone's collection who is interested in sports timing.
 Seiko Watch Catalog ‘77 Vol.1. Seiko Watch Corp., 1977, pp.119
 Goodall, John. A Journey in Time, The Remarkable Story of Seiko. Seiko Watch Corporation, 2003, pp.95
 Tatsuya, Ishihara. “About Start Stop Error of Stopwatch.” Japanese Clock Journal, Vol.29, 1964, pp.10
 Seiko Instruments Inc. Time measuring instrument. US3168803A, United States Patent and Trademark Office, 9 February 1965. Google Patents, https://patents.google.com/patent/US3168803A/en?oq=US3168803A
 Komaki, Shoichiro. Lectures on Mechanical Watch. University of Tokyo Press, 2014, pp.218
 The Seiko Book. Town Mook, Tokuma Shoten, 1999, pp.152
 The Seiko Book. Town Mook, Tokuma Shoten, 1999, pp.151
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 "Our Challenge to become the Official Timer of the Olympics | Seiko ...." https://museum.seiko.co.jp/en/seiko_history/milestone/milestone_01/. Accessed 29 Jun. 2019.
 Goodall, John. A Journey in Time, The Remarkable Story of Seiko. Seiko Watch Corporation, 2003, pp.76
 “Seiko’s Stopwatch.” Horological International Correspondence, Vol.3 No.29, 1962, pp.482
 Tanaka, Taro. “Mysterious Stopwatches.” Horological International Correspondence, Vol.37 No.432, 1996, pp.114
 Sports Timers for the XVIII Olympic Games, OOC-A-133, Seiko, 1963, pp.21
[16a] Goodall, John. A Journey in Time, The Remarkable Story of Seiko. Seiko Watch Corporation, 2003, pp.99
[16b] Universiade 1967 Tokyo Official Timing Of. K. Hattori & Co. Ltd., 1967, pp.7-8
 Seiko Timing Systems for Sapporo Winter Games. K. Hattori & Co. Ltd., 1971, pp.38
 Seiko Timing Systems for Winter Sports, Seiko News, K. Hattori & Co. Ltd., 1971
 Sapporo Timing Devices Product Images. Seiko, K. Hattori & Co. Ltd., 1973
 Tanaka, Taro. “Mysterious Stopwatches.” Horological International Correspondence, Vol.37 No.432, 1996, pp.116
 "投稿掲示板 - SII社友会., About book cover photograph of "mechanical watch course" , Posted by: Shoichiro Komaki Posted Date: 2014/11/25 09:00 #965, "http://sii-shayuukai.com/modules/yybbs/viewbbs.php?start=85&bbs_id=1, Accessed 29 Jun. 2019.
 The Mainichi Graphic, Special Edition, The Mainichi Newspapers, 29 February 1972
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 Seiko Watch Catalog ‘77 Vol.1. Seiko Watch Corp., 1977, pp.98
 Seiko Watch Catalog ‘77 Vol.1. Seiko Watch Corp., 1977, pp.119