Grand Seiko is a line of luxury watches manufactured by Seiko and a separate brand since 2017.

The Grand Seiko brand was launched in 1960 as Japan was rising to be a center of precision manufacturing and vying for a place in the pantheon of first-world countries. The company had produced high-quality watches previously, including Lord Marvel, Crown and Chronos, but Grand Seiko would be a halo brand for the entire company. Seiko had two competitive divisions manufacturing watches at that time, Daini and Suwa, and selected the former for the initial Grand Seiko project. Eventually, both would contribute to the line.

The Grand Seiko line was retired in 1976 as quartz movements took hold. But the company revived the brand a decade later, introducing a quartz Grand Seiko for the first time in 1986. As mechanical watches regained market share, Seiko responded, re-launching the Grand Seiko mechanical line in 1998. It became a halo for the company, with the return of GMT in 2002, the introduction of a Grand Seiko Spring Drive model in 2004, and the return of a Hi-Beat model in 2009. In 2017, Seiko officially split Grand Seiko from the mother company, launching it as a brand in its own right and removing “Seiko” from the dial once again.

Seiko's first designer, Taro Tanaka, was tasked with elevating Seiko's high-end products and defining a style of their own. He noticed that Swiss watches “sparkled brilliantly” and realized that it was a combination of sharp edges, mirror finish, and brushed surfaces that could create a distinctive Japanese look to the company's watches. His ideas were first implemented with the 1967 Grand Seiko 44GS, one of the most famous designs of the classic Seiko era. Although Seiko continued to produce a variety of cases for Grand Seiko and King Seiko watches, Tanaka's “Grand Seiko Style” models are best remembered today. This includes the 8000-series cases on the 61GS, 45GS, and 56GS, the 56GS 7010/7011/7030 cases, and the 61GS 7000/8010/8020/8040/8050.

It was also reused after the demise of the Grand Seiko on the Grand Quartz 4842-8041 of the late 1970's. This style has continued with the reborn Grand Seiko since 1998. Many modern Grand Seiko models feature cases that are obviously derived from this classic “Grammar”, but a few go further The modern SBGW043/44/46/47 are considered “reissues” of the 44GS, while the SBGR081/83 is a homage.

Introduced in June, 1956, the Marvel was the first wholly in-house watch created by Daini Seikosha. From 1958, “Lord Marvel” blazed the path for the later creation of the Grand Seiko series, originally by Suwa Seikosha, and it would become the highest-standard watch from Seiko throughout the 1960's. Lord Marvels pioneered “Hi-Beat” movements for Seiko, and were among the most accurate watches produced by the company. The final Lord Marvel used the 5740C movement and was produced from 1967 through 1978, making it Seiko's final high-end mechanical watch before the renaissance of Grand Seiko in 1998. Seiko also used the “Lord” name on the midrange “Lord Matic” line.

Seiko allowed Suwa Seikosha to develop the Grand Seiko in 1960, and their models focused on quality mechanics. Daini Seikosha got in on the action, migrating their King Seiko to the Grand Seiko line and setting the styling standards for all future Seiko products. Grand Seiko moved to “Hi-Beat” 36,000 A/h movements in 1968 and many featured accuracy surpassing Swiss chronometers. But the line came to an end in 1976 as the quartz revolution temporarily eliminated the market for high-accuracy mechanical watches.

• Grand Seiko (1960-1964) - Calibre 3180, produced by Suwa, 18,000 A/h, self-certified chronometer
• 57GS (1963-1968) - “Self Dater” - Model 430/5722A/5722B, produced by Suwa, 18,000/19,800 A/h, self-certified chronometer
• 44GS (1967-1968) - “Grand Seiko Style” - Calibre 4420A/4420B, produced by Daini, 18,000 A/h
• 62GS (1967-1969) - “Self Winding” - Calibre 6245A/6246A, produced by Suwa, 19,800 A/h
• 61GS (1968-1975) - “Automatic Hi-Beat” - Calibre 61xx, produced by Suwa, automatic, 36,000 A/h
• 45GS (1968-1973) - “Manual Hi-Beat” - Calibre 45xx, produced by Daini, manual, 36,000 A/h (also VFA and Astronomical Observatory models)
• 19GS (1968-1974) - “Grand Seiko for Women - Calibre 19xx, 36,000 A/h
• 56GS (1970-1975) - “Ultra Thin” - Calibre 56xx, produced by Suwa, automatic, 28,800 A/h

With Suwa Seikosha getting the Grand Seiko line, Daini Seikosha produced their own high-end lineup. King Seiko featured trend-setting style and case design, existing as competition for Grand Seiko throughout the classic period. Automatic movements were introduced in 1968 with the 56KS.

• King Seiko (1961-1964) - Produced by Daini
• 44KS (1964-1968) - “Grand Seiko Style” - Calibre 4420A/4420B, produced by Daini, 18,000 A/h
• 45KS (1968-1973) - “Hi-Beat” - Calibre 45xx, produced by Daini, 36,000 A/h
• 56KS (1968-1975) - “King Seiko Automatic” - Calibre 56xx, produced by Suwa, automatic, 28,800 A/h
• 52KS (1971-1975) - “Final King Seiko” - Calibre 52xx, produced by Daini, automatic, 28,800 A/h

Seiko introduced high-accuracy quartz movements in Grand Seiko models in 1988, reviving the brand after a decade-long absence.

• Grand Seiko 95GS Quartz (1988)
• Grand Seiko 3FGS Quartz for Women (1992)
• Grand Seiko 9F8 Quartz (1993) - “Quartz that surpasses quartz”
• Grand Seiko SBGX Quartz (2003) - 9F61
• Grand Seiko SBGX Quartz (2003?) - 9F61/62
• Grand Seiko SBGT Quartz Day/Date (2010?) - 9F83
• Grand Seiko SBGX Antimagnetic (2012) - 9F61
• Grand Seiko SBGV Quartz Tribute Self Dater (2014) - 9F82

Mechanical Grand Seiko models were reintroduced in late 1998 using updated versions of the 5200 calibre, now called the 9S family. The first models used the 9S51 and 9S55, but the line has expanded greatly since then. Today, all high-end Seiko timepieces are manufactured at Shizukuishi Watch Studio.

• Grand Seiko SBGR Automatic (1998) - 9S51/54/55/56/65/67, 28,800 A/h, date
• Grand Seiko SBGW Manual Winding (2001) - 9S54/64, 28,800 a/H, manual
• Grand Seiko SBGM Automatic GMT (2002) - 9S56/66, 28,800 A/h, date, GMT
• Grand Seiko SBGL 3 Days Power Reserve (2006) - 9S67, 28,800 A/h, date, power reserve indicator
• Grand Seiko SBGH Hi-Beat (2009) - 9S85, 36,000 A/h, date
• Grand Seiko SBGR Automatic 3 Days (2010) - 9S65, 28,800 A/h, date
• Grand Seiko SBGR Antimagnetic (2012) - 9S65, 28,800 A/h, date
• Grand Seiko SBGJ Hi-Beat GMT (2014) - 9S86, 36,000 A/h, date, GMT
• Grand Seiko STGK Ladies (2018) - 9S25/27, 28,800 A/h, date

Seiko's Spring Drive movement is a high-accuracy mechanical movement with a quartz-timed electromagnetic regulator and was released to market in 1999.

• Grand Seiko SBGA Spring Drive Power Reserve (2004) - 9R15/65
• Grand Seiko SBGE Spring Drive GMT () - 9R66
• Grand Seiko SBGC Spring Drive Chronograph (2007) - 9R86
• Grand Seiko SBGC Spring Drive Chronograph (new case) (2019) - 9R96
• Grand Seiko SBGZ Spring Drive Hand-Winding (2019) - 9R02
• Grand Seiko SBGY Spring Drive Hand-Winding (2019) - 9R31

• History of Grand Seiko
• The History of Grand Seiko
• Grand Seiko 130th Anniversary SBGW040
• The History of Grand Seiko Hi-Beat Movements: Seiko's Affinity to Hi-Beat Movement -- Part One
• The History of King Seiko: Seiko's Affinity to Hi-Beat Movement -- Part Two
• The Story of Grand Seiko: From the Pages of Watchtime Magazine
• Interview: Akira Ohira - watchmaking "Father" of modern mechanical Grand Seiko