Having two companies both producing the same brand of watch enabled Seiko to improve technology through competition and hedge risk.

Around the time of Seiko's founding, watchmakers 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.

[13][14] In 1885, 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.

[15] Over the years, Hattori developed a close partnership with multiple foreign trading firms, including 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 elsewhere at that time.

The 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.

In 1892, Hattori began to produce clocks under the name Seikosha (精工舎, Seikōsha), meaning, roughly, "House of Exquisite Workmanship."

[20] In 1895, the watch dealer purchased the corner of Ginza 4-chome (the present-day location of WAKO), and constructed a building with a clock tower (16 meters from top to bottom), setting up shop at the new address.

[5] In order to avoid an ill omen believed to be associated with the word "GLORY" in Japanese, Seikosha changed its trade mark to "Seiko" in 1924.

The scarcity of raw materials during the war diverted much of Seiko's production to on-board instruments for military aircraft and ships.

In the same year, the company released the Marvel, which represented a significant improvement in accuracy, quality, and productivity over the previous model.

The Magic Lever was simple in structure and had high winding performance, and popularized automatic watches among the general public.

The quartz clock Seiko had supplied to a broadcasting station in 1959 was about the size of a wardrobe, but this new product ran on two batteries and was portable.

[5][24] In 1969, Seiko launched the Astron, the world's first commercial quartz wristwatch; when it was introduced, it cost the same as a medium-sized car.

In the same year, Seiko introduced the Five Sport Speed Timer, the world's first Magic Lever watch with a vertical clutch and column wheel.

[23] In 2005, Seiko launched the world's first solar-powered analog watch that adjusts its accuracy by receiving three radio signals from Japan, Germany, and the United States.

Seiko positioned this watch as the second revolutionary wristwatch after the Astron, which was launched in 1969, and described that it had the ultimate practical functionality, being able to instantly display extremely accurate time anywhere in the world and working as long as there is light.

It was launched worldwide with a million units, symbolizing Seiko's partnership with the world's no.1 professional tennis player.

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).

The Seiko Lord Matic series of wristwatches was a mid-range sub-luxury watch of the 1970s that featured design innovations such as faceted crystals, colorful dials and sporty bracelets.

In 2021, Akio Naito, President of the Seiko Watch Corporation,[37] said that enthusiasts' respect for the brand can "influence the wider range of consumers.

"[38] This influence can be seen in the Prospex range, where Seiko fans' nicknames resulted in the company eventually adopting these product names.

The first King Seikos were made with unmarked, manual winding, 25 jewel movements, that were not internally tested chronometers.

In 1968, the 45KS was introduced with a manual winding, 36,000 bph hi-beat movement – again meant to compete with the 45GS but generally less accurate and with less finishing.

During the ten years of development at Suwa Seikosha, Seiko managed to create many parts which enabled the viable application of quartz in wristwatches.

Although creating the parts that enabled quartz watches, Seiko did not monopolize the patent rights for the unique pieces, but decided to open them.

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.

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.

[79] Seiko developed a digital watch styled after Venom Snake's timepiece in Metal Gear Solid V: The Phantom Pain under its Wired brand.

[80][81] Seiko is also named as the official timekeeper of the Gran Turismo racing game series, published by Sony Computer Entertainment.