|Founded||Chūō, Tokyo, Japan|
(incorporated in 1917)
|Headquarters||1-26-1 Ginza, Chūō, Tokyo, Japan|
(Officially registered at 4-5-11 Ginza, Chūō, Tokyo, Japan)
|Products||Watches, clocks, jewelries, electronic devices, apparel, printers, semiconductors, musical instruments, lenses|
|Revenue||¥239 billion (2020)|
|¥5.17 billion (2020)|
|¥3.4 billion (2020)|
|Total assets||¥299 billion (2020)|
|Total equity||¥103 billion (2020)|
Number of employees
Seiko Holdings Corporation (セイコーホールディングス株式会社, Seikō Hōrudingusu Kabushiki-gaisha), commonly known as Seiko (// SAY-koh, Japanese: [seːkoː]), is a Japanese maker of watches, clocks, electronic devices, semiconductors, jewelries, and optical products. Founded in 1881, it is known for introducing one of the world's first quartz wrist watches as well as the world's first quartz watch with a chronograph complication.
History and development
Kintarō Hattori had been working as clockmaker apprentice since the age of 13, with multiple stints in different watch shops, such as “Kobayashi Clock Shop”, ran by an expert technician named Seijiro Sakurai, “Kameda Clock Shop” in Nihonbashi, as well as “Sakata Clock Shop” in Ueno, where he learned how to both sell and repair timepieces.
In 1881, a new age of Japan-made clocks and watches was dawning. Pioneers in Tokyo, Osaka, and Nagoya were studying and producing pocket watches based on Western products. Japanese wholesalers needed to purchase all the imported timepieces from foreign trading companies established in Yokohama, Kobe, and other open port areas. 
In 1885, Mr. Hattori began dealing directly with these foreign trading firms in the Yokohama settlement focused on the wholesaling and retailing of western (imported) timepieces and machinery.
Over the years, Kintarō Hattori developed a close partnership with multiple foreign trading firms, including the likes of C&J Favre-Brandt, F. Perregaux & Co., Zanuti & Cie. and Siber & Brennwald, allowing him to obtain exclusive imported timepieces and machinery which was not available to anyone else at that time.   
Mr. Hattori's shop became increasingly popular due to the rarity of the imported watches the shop was selling, items that couldn't be found anywhere else in Japan. This growing success allowed him to relocate the company to the main street of Ginza (Tokyo), still the epicenter of commerce in Japan to this day.
The amount of support from his customers encouraged Mr Hattori to pursue the next step, which was becoming a manufacturer himself, an endeavor he would pursue shortly after by purchasing a factory in Tokyo and renaming it 'Seikosha' (精工舍).
In 1891, 10 years after the establishment of K. Hattori & Co., the 31-year-old Kintaro was asked to take up two important positions in industry, one as a director of the Tokyo Clockmaker and Watchmaker Association and one as a member of Tokyo Chamber of Commerce.
Eight years later, in 1895, the successful watch dealer purchased the whole corner of Ginza 4-chome (the present-day location of WAKO), constructed a building with a clock tower (16 meters from top to bottom), setting up shop at the new address.
In 1892, Mr. Hattori began to produce clocks under the name Seikosha (精工舎, Seikōsha), meaning roughly, "House of Exquisite Workmanship". According to Seiko's official company history, titled A Journey In Time: The Remarkable Story of Seiko (2003), Seiko is a Japanese word with the character meaning "exquisite" (精巧, Seikō); it is homophonous with the word for "success" (成功, Seikō).
In 1969, Seiko introduced the Astron, the world's first production quartz watch; when it was introduced, it cost the same as a medium-sized car. Seiko later went on to introduce the first quartz chronograph.
In the late 1980s, Seiko produced the first automatic quartz that combined the self-energizing attributes of an automatic watch with quartz accuracy. The watch is entirely powered by its movement in everyday wear. In 1991, to increase popularity, these watches were relaunched under the name Seiko Kinetic.
The company was incorporated (K. Hattori & Co., Ltd.) in 1917 and was renamed Hattori Seiko Co., Ltd. in 1983 and Seiko Corporation in 1990. After reconstructing and creating its operating subsidiaries (such as Seiko Watch Corporation and Seiko Clock Inc.), it became a holding company in 2001 and was renamed Seiko Holdings Corporation as of July 1, 2007.
Seiko is perhaps best known for its wristwatches, all of which were at one time produced entirely in house. This includes not only major items such as microgears, motors, hands, crystal oscillators, batteries, sensors, and LCDs, but also minor items such as the oils used in lubricating the watches and the luminous compounds used on the hands and the dials. Seiko watches were originally produced by two different subsidiaries. One was Daini Seikosha Co.,(now known as Seiko Instruments Inc.), and the other was Suwa Seikosha Co.(now known as Seiko Epson Corporation). Having two companies both producing the same brand of watch enabled Seiko to improve technology through competition and hedge risk. It also reduced risk of production problems, since one company can increase production in the case of decreased production in the other parties.
Currently watch movements are made in Shizukuishi, Iwate (SII Morioka Seiko Instruments), Ninohe, Iwate (SII Ninohe Tokei Kogyo), Shiojiri, Nagano (Seiko Epson) and their subsidiaries in China, Malaysia and Singapore. The fully integrated in-house production system is still practiced for luxury watches in Japan.
Seiko in the United States
Seiko Corporation of America is responsible for the distribution of Seiko watches and clocks, as well as Pulsar and Lorus brand watches, in the United States. The models available in the United States are normally a smaller subset of the full line produced in Japan. Seiko Corporation of America has its headquarters (and Coserv repair center) in Mahwah, New Jersey. In the United States, Seiko watches are sold primarily by fine jewelers and department stores as well as 19 company stores located in various cities.
On Friday, January 10, 2014 on the eve of the Australian Open in Melbourne, Shinji Hattori, President of Seiko Watch Corporation, presented to Novak Djokovic a Seiko 5 limited edition worth $1700. It was launched worldwide with a million units, symbolizing Seiko's partnership with the world's no.1 professional tennis player.
Seiko Holdings is one of the three core companies of the Seiko Group. The Seiko Group consists of Seiko Holdings Corporation (Seiko), Seiko Instruments Inc. (SII), and Seiko Epson Corporation (Epson). Although they have some common shareholders, including the key members of the Hattori family (posterity of Kintarō Hattori), the three companies in the Seiko Group are not affiliated. They are managed and operated completely independently. Seiko Watch, an operating subsidiary of Seiko Holdings, markets Seiko watches, while SII and Epson manufacture their movements.
On January 26, 2009, Seiko Holdings and Seiko Instruments announced that the two companies would be merged on October 1, 2009, through a share swap. Seiko Instruments became a wholly owned subsidiary of Seiko Holdings as of October 1, 2009.
- Seiko Watch Corporation — Planning for watches and other products and domestic and overseas sales
- Seiko Nextage Co., Ltd. — watches: Alba and licensed brand watches
- Seiko Clock Inc. — Development, manufacturing and sales of clocks (desk clocks, wall clocks, alarm clocks)
- Seiko Service Center Co., Ltd. — repair and after service for watches
- Seiko Time Systems Inc. — Sale and incidental installation work for system clocks, varied information display equipment and sports timing equipment, as well as timing and measurement services for various sports
- Seiko Precision Inc. — Manufacturing/sales for electronic devices, shutters for cameras and peripherals, and production equipment
- Seiko NPC Corporation — Development, manufacturing and marketing of integrated circuits (IC)
- Seiko Solutions Inc. — Development, manufacturing, sales, maintenance, services and consultations for the hardware and the software relating with information systems and network services
- Seiko Optical Products Co., Ltd. — Wholesale marketing of lenses and frames for glasses along with other optical-related products
- Seiko Instruments Inc. — Development, manufacturing and sales of watches, precision components and machine tools, electronic components, printers, measurement and analysis instruments
- Wako Co., Ltd. — Sales of watches, jewelry, accessories, interior supplies, art goods and crafts, glasses and foodstuffs
- Cronos Inc. — retail sales of watches, jewelry items and eyeglasses
- Seiko Business Services Inc. — human resources
- Ohara Inc. (Seiko owns 32.2% TYO: 5218) — specialty optical glass (glass materials for lenses and prisms)
Brands and product lines
Seiko produces watches with quartz, kinetic, solar, and mechanical movements of varying prices, ranging from around ¥4,000 (US$45) to ¥50,000,000 (US$554,000). To separate the customer groups, Seiko has created many different brands in Japan and the international market including Lorus, Pulsar, and Alba.
The Seiko 5 is a standard that many Seiko mechanical watch models meet since the introduction of the Seiko 5 in the 1960s.
Watches get this name as they exhibit the following five principles:
- It must feature an automatic watch movement
- It must display the day and the date on the dial
- It must be water resistant to an acceptable degree
- It must have a recessed crown at the 4 o'clock position
- It must have a durable case and bracelet
Seiko has made many different models of the "5" standard watch, including large as well as small divers, watches featuring different strap options such as leather or even nylon, transparent or sterile case-back versions and many other variations. Today, the Seiko 5 lineup mostly comprises entry-level mechanical watches that act as an affordable entry point for consumers looking to enter the world of automatic watches.
NASA Flight Director Gene Kranz wore a Seiko 5 model 6119-8460 during the height of his career. It was on his wrist when the Apollo 11 crew touched down on the lunar surface, when the Apollo 13 explosion occurred, and throughout the remainder of his career at NASA.
The Seiko Presage series is an all-mechanical lineup, a step up from the entry-level Seiko 5 models. It has slightly more elaborate designs and complex movements, such as urushi-lacquer dials, and self-winding movements with power reserve indicators. The Presage line watches are usually priced between US$200 to US$3,000.
The Seiko Prospex series includes their professional series of watches such as their diving watches, which are typically ISO 6425 rated from 200 to 1000 metres of water resistance. Other watches in the Prospex line include field and pilot style watches.
Prior to 1960, to challenge the status of Swiss watches and change the perception of Japanese watches, Daini Seikosha and Suwa began the discussion of a product line that can match the quality of Swiss watches under the suggestion of the parent company. At the time, Suwa Seikosha Co. was in charge of manufacturing men's watches, so it was decided that Suwa would be producing the first Grand Seiko (GS).
The first Grand Seiko was released in 1960, it was based on Seiko's previous high-end watch, CROWN. This Grand Seiko has a 25-jewel, manual-winding, 3180 caliber, and only 36,000 units were produced. This was also the first chronometer-grade watch manufactured in Japan, and it was based on Seiko's own chronometer standard.
Some Grand Seiko timepieces also incorporate the company's revolutionary Spring Drive movement, a movement that is a combination of both automatic and quartz timekeeping methods, leading to unparalleled accuracy in the world of automatic wristwatches, the most famous of which is the SBGA011 Grand Seiko "Snowflake", housing the 9R Spring Drive movement as seen on the right.
The design language of the Grand Seiko was set in 1967, with the creation of Grand Seiko 44GS. The 44GS set the ground for all future Grand Seiko with nine elements. These elements help improve the legibility of the watch under different situations, and create a sharp, crisp visual impression:
- Double width index at 12 o'clock
- Multi-faceted rectangular markers
- Highly polished bezel
- Highly polished planes and two-dimensional surface
- Half recessed crown
- Flat dial
- Multi-faceted hour and minute hands
- Curved side line
- Reverse slanted bezel wall and case side
- Dress style with simple but beautiful design
- Zaratsu polishing
Seiko produces electronic devices as well. During the 1980s, the company produced a notable range of digital synthesizers, such as the DS-250, for use in electronic music. Today the music division (part of Seiko Life Sports) produces metronomes and tuning devices.
In 1968, Seiko introduced three ten beat (ten ticks per second) calibers, the automatic caliber 61GS, the manual winding 45GS and 19GS for women's watch. The 61GS was Japan's first automatic ten beat watch, and it was the most accurate mechanical watch due to the high beat calibers. The calibers are considered high beat because normal mechanical movements beat six to eight times per second, and higher beat makes the watch more resistant to shock, thus achieving the high accuracy.
In 2009, Seiko released the new ten beat caliber 9S85, which is a completely new design from the previous high beat caliber. The new caliber also met the Grand Seiko Standard, a chronometer certification that the company claims to be more strict than the Chronometer Certificate in Switzerland.
List of Seiko mechanical movements
|4R35||21,600||24||+45～-35||40||3 hands, time display (Hour, minute and second hands) and date display|
|4R36||21,600||24||+45～-35||40||3 hands, time display (Hour, minute and second hands) and day and date display|
|6R15||21,600||23||+25～-15||50||3 hands, time display (Hour, minute and second hands) and date display|
|6R20||28,800||29||+25～-15||45||6 hands, time display (Hour, minute and second hands), day and date display, power reserve indicator|
|6R21||28,800||29||+25～-15||45||6 hands, time display (Hour, minute and second hands), day and date display, power reserve indicator|
|6R24||28,800||31||+25～-15||45||6 hands, time display (Hour, minute and second hands), day and date display, power reserve indicator|
|6R27||28,800||29||+25～-15||45||5 hands, time display (Hour, minute and second hands), date display, power reserve indicator|
|6R35||21,600||24||+25～-15||70||3 hands, time display (Hour, minute and second hands) and date display|
|7S26||21,600||21||+40～-20||41||3 hands, time display (Hour, minute and second hands) and date display|
|7S36||21,600||23||+40～-20||41||3 hands, time display (Hour, minute and second hands) and date display|
|8R28||28,800||34||+25～-15||45||6 hands, time display (Hour, minute and small second hands), stopwatch display (Hour, minute and second hands) and date display|
|8L35||28,800||26||+15～-10||50||3 hands, time display (Hour, minute and second hands) and date display|
|8L55||36,000||37||+15～-10||55||3 hands, time display (Hour, minute and second hands) and date display|
On December 25, 1969, Seiko released the world's first quartz watch, the Seiko Quartz ASTRON, which marked the beginning of the quartz revolution. The watch uses a crystal oscillator for accuracy, where the crystal generates steady vibration when voltage is applied to it. During the ten years of development at Suwa Seikosha, Seiko managed to create many parts which enabled the viable application of quartz in wristwatches. For example, Seiko cut the crystal oscillator into the shape of a tuning-fork, and developed an integrated circuit and step motor to operate with the signals from the crystal oscillator.
Although creating the parts that enabled quartz watches, Seiko did not monopolize the patent rights for the unique pieces, but decided to open them.
In 1973, Seiko announced the world's first LCD quartz watch with six-digit digital display.
In 1975, Seiko launched the world's first multi-function digital watch, the 0634.
In 1978, Seiko released the Twin Quartz watch to address the impact of temperature on the frequency of the quartz crystal oscillator, which put a limitation on the accuracy of quartz watches. Seiko put a second crystal in the watch that is linked with a processor that detects the change in temperature and signals the main oscillator to compensate. The result was a huge improvement in the watch's accuracy from 5 seconds per month to 5 seconds per year.
Kinetic watches were introduced by Seiko in 1986 at the Basel Fair Trade Show. These quartz watches use the motion of the wearer's wrist to charge their battery.
Grand Seiko 9F quartz movement
The 9F quartz movement is used in Grand Seiko quartz watches.
The Grand Seiko's 9F quartz movement is assembled entirely by hand by two expert craftsmen.
- Backlash auto-adjust mechanism
- Twin pulse control motor
- Instant date change mechanism – it can change the date display in 1/2000th of a second
The Spring Drive was announced in 1997. It was developed by Yoshikazu Akahane and his team and inspired by Yoshikazu's vision: "a watch wound by a mainspring and with one-second-a-day accuracy, a precision that only the finest electronic watches could deliver". This movement achieved high accuracy with one second per day, long power reserve (72 hours) with its special developed alloy, fast winding with the "Magic Lever" design and glide-motion movement with the watch hands.
The movement uses a mainspring as a source of energy and transmits it through a gear train, just like a traditional mechanical watch, but instead of an escapement and balance wheel, Seiko used the newly developed "Tri-synchro regulator", which acts like a quartz movement. The Tri-synchro regulator has three main functions: controlling the mechanical energy of the mainspring, generate electricity for the low consumption (~25 nanowatts) quartz crystal oscillator and generate a magnetic force to regulate the glide wheel. By replacing the traditional escapement with a magnetic brake, the Spring Drive operates with lower noise and presents a glide motion hand that shows the continuous flow of time. The Spring Drive movement was also used as the basis for the first-ever watch designed to be worn by an astronaut during a space walk, the aptly named Seiko Spring Drive Spacewalk.
Seiko has been the official timekeeper of many major sporting events:
- 1964 Summer Olympics in Tokyo, Japan
- 1972 Winter Olympics in Sapporo, Japan
- 1992 Summer Olympics in Barcelona, Spain
- 1994 Winter Olympics in Lillehammer, Norway
- 1998 Winter Olympics in Nagano, Japan
- 2002 Winter Olympics in Salt Lake City, Utah, United States
FIFA World Cup
- 1978 FIFA World Cup in Argentina
- 1982 FIFA World Cup in Spain
- 1986 FIFA World Cup in Mexico
- 1990 FIFA World Cup in Italy
IAAF World Championships
Currently, Seiko has an agreement with World Athletics to act as the timekeeper for the latest editions of the World Athletics Championships. The agreement started in 1985 and is set to continue until at least 2029.
- 1987 World Championships in Athletics in Rome, Italy
- 1991 World Championships in Athletics in Tokyo, Japan
- 1993 World Championships in Athletics in Stuttgart, Germany
- 1995 World Championships in Athletics in Gothenburg, Sweden
- 1997 World Championships in Athletics in Athens, Greece
- 1999 World Championships in Athletics in Seville, Spain
- 2001 World Championships in Athletics in Edmonton, Canada
- 2003 World Championships in Athletics in Paris, France
- 2005 World Championships in Athletics in Helsinki, Finland
- 2007 World Championships in Athletics in Osaka, Japan
- 2009 World Championships in Athletics in Berlin, Germany
- 2011 World Championships in Athletics in Daegu, South Korea
- 2013 World Championships in Athletics in Moscow, Russia
- 2015 World Championships in Athletics in Beijing, China
- 2017 World Championships in Athletics in London, United Kingdom
- 2019 World Championships in Athletics in Doha, Qatar
- 2022 World Athletics Championships in Eugene, United States
Throughout the history, Seiko has been the official timekeeper for many tennis tournaments.
- Seiko Super Tennis in Tokyo, Japan (1978–1995)
- French Open in Paris, France (1980–1991)
- Pan Pacific Open in Tokyo, Japan and later in Osaka, Japan (1984–present)
Seiko developed a digital watch styled after Venom Snake's timepiece in Metal Gear Solid V: The Phantom Pain under its Wired brand. It was launched on September 2, 2015 with the Metal Gear installment. It was limited to 2,500 pieces worldwide and was sold out via pre-orders within 5 minutes of launch. The box of the watch was designed by Metal Gear Solid artist Yoji Shinkawa. Seiko is also named as the official timekeeper of the Gran Turismo racing game series, published by Sony Computer Entertainment. It was also the sponsor of FC Barcelona from 2011 to 2014.
Seiko used to sponsor Honda F1 (previously known as BAR [British American Racing] Honda). The Honda team driver Jenson Button was the brand ambassador of Seiko. The company name only appeared on the team's clothing, Button's helmet and on the pitstop lollipops. The sponsorship lasted until the end of the 2008 season when Honda pulled out of F1 racing.
Historic Seiko watches
Seiko LCD Solar Alarm Chronograph A156-5000, 1978 (Seiko's 1st solar-powered watch)
References and footnotes
- Notification of change of President Seiko Holdings Corporation, April 30, 2010
- "Corporate Information". Seiko. Retrieved 18 July 2020.
- "Seiko Holdings Corporation Financial Statements" (PDF). Seiko Holdings Corporation. Retrieved May 6, 2020.
- "History of Seiko and Its Products". THE SEIKO MUSEUM. Retrieved 2017-10-14.
- Historical references, Ginza Museum
- Spirit of Kintaro Hattori, the Founder (SEIKO)
- Impact of the western companies of Yokohama
- Foreign trading firms in Yokohama
- Historical references from 1860 to 1880
- K. Hattori & Co. (1881 - 1891)
- Episode 3 (1892) Seikosha Factory
- John Goodall (2003). A Journey In Time: The Remarkable Story of Seiko. Seiko Watch Corporation. p. 9.
- "TRADE MARKS ORDINANCE (CAP. 559) OPPOSITION TO TRADE MARK APPLICATION NO. 301488619" (PDF). Retrieved 2019-12-11.
- Adv. "How could we fit 50 patents inside? We took out the battery". Newsweek. December 18, 1995. p. 15.
- "Copy Swiss Replica Watches".
- "Novak Djokovic Signs with Seiko". Retrieved 2017-10-12.
- Credor FUGAKU GBCC999 (in Japanese)
- "WHY "5" ? | THE SEIKO 5 STORY | SEIKO 5 SPORTS". www.seikowatches.com. Retrieved 2017-10-14.
- December 08, Jack Forster; 2016. "Introducing: The Seiko Presage Automatic 60th Anniversary Limited Edition, SARW027". HODINKEE. Retrieved 2019-12-12.CS1 maint: numeric names: authors list (link)
- "What Is The History Of Seiko? | Automatic Watches For Men". Retrieved 2019-12-12.
- "The Shippo Enamel Limited Edition | Presage | SEIKO WATCH CORPORATION". The Shippo Enamel Limited Edition | Presage | SEIKO WATCH CORPORATION. Retrieved 2020-10-14.
- "Baselworld 2018 Releases - Seiko Presage". Plus9Time. Retrieved 2020-10-14.
- "The History of Grand Seiko". seiyajapan.com. Retrieved 2016-12-02.
- "DESIGN | ABOUT | Grand Seiko". www.grand-seiko.com. Retrieved 2017-12-12.
- "Grand Seiko GS 45GS V.F.A." strapcode.com. Retrieved 2020-10-07.
- "Grand Seiko for Women 19GS". strapcode.com. Retrieved 2020-10-07.
- "Grand Seiko | SEIKO WATCH CORPORATION". www.grand-seiko.com. Retrieved 2016-12-02.
- "Grand Seiko Hi Beat Caliber 9S85". strapcode.com. Retrieved 2020-10-07.
- "Grand Seiko Caliber 9S85". calibercorner.com. Retrieved 2016-12-02.
- "Grand Seiko | SEIKO WATCH CORPORATION". www.grand-seiko.com. Retrieved 2016-12-02.
- October 10, Joe Thompson; 2017. "Four Revolutions: Part 1: A Concise History Of The Quartz Revolution". HODINKEE. Retrieved 2019-03-05.CS1 maint: numeric names: authors list (link)
- "The Quartz Crisis and Recovery of Swiss Watches | Relation between Timepieces and Society". THE SEIKO MUSEUM. Retrieved 2019-03-05.
- "The Quartz Crisis". Crown & Caliber Blog. 2018-04-12. Retrieved 2019-03-05.
- "About Seiko Kinetic watches and Kinetic Movements". Strapcode.com.
- "9F Quartz | MOVEMENT | ABOUT | Grand Seiko". www.grand-seiko.com. Retrieved 2017-12-17.
- "SEIKO WATCH | Technology - Spring Drive". SEIKO WATCH. Retrieved 2016-10-28.
- ""SEIKO wins the prestigious Sports Watch of 2010 award at the Grand Prix d'Horlogerie de Genève"". seikowatches.com. Retrieved 2017-10-12.
- "Seiko and the 2002 FIFA World Cup™". Europa Star. February 2001. Retrieved 5 March 2021.
- "Partners - Seiko". IAAF. Retrieved 5 March 2017.
- "Seiko renews its partnership with the IAAF for ten more years". Yokohama: World Athletics. 10 May 2019. Retrieved 9 July 2019.
- "History of Seiko and Sports". Seiko. Retrieved 1 January 2021.
- "Watch Identifier: Seiko Wired Metal Gear Solid Watch Review". Keep The Time. Retrieved July 29, 2020.
- Espineli, Matt (November 25, 2015). "Here's What a $375 Metal Gear Solid Watch Looks Like". GameSpot. Retrieved July 29, 2020.
- "Seiko is the Official Timekeeper of the Gran Turismo Racing Series". Luxury Watches That Impress Review Blog. 1 February 2012. Retrieved 3 August 2019.
- "SEIKO's sponsorship of FC Barcelona is celebrated in Turkey". Seiko. Istanbul. 28 May 2011. Retrieved 2 March 2017.
- "FC Barcelona to swap Seiko for Maurice Lacroix". Goal.com Singapore. 11 March 2014. Retrieved 2 March 2017.
- "NASL welcomes Seiko as official timekeeper". NASL. 11 April 2014. Retrieved 2 March 2017.
- "Seiko extends Honda deal". AutoSport. March 1, 2006. Retrieved July 29, 2020.
- "Honda pulls out of Formula One". EuroSport. December 5, 2008. Retrieved July 29, 2020.
- Derr, Elizabeth (16 December 2016). "Seiko Nets Renewed Partnership With Novak Djokovic". Forbes. Retrieved 1 January 2021.
- Donzé, Pierre-Yves. "Dynamics of innovation in the electronic watch industry: a comparative business history of Longines (Switzerland) and Seiko (Japan), 1960-1980." Essays in Economic & Business History 37.1 (2019): 120-145. online
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