Seiko Spring Drive Hand-wound Limited Edition, References SBWA001 and SBWA002

Seiko Spring Drive is a mechanical watch having accuracy equivalent to a quartz watch. This innovative technology was announced by Seiko at the 1998 Basel Fair. The first Seiko branded Spring Drive wristwatch models to be introduced into the market were SBWA001 and SBWA002.

Traditionally, the energy source of a mechanical timepiece is the mainspring and the regulating components are the balance spring and the escapement. The Spring Drive is powered by a mainspring just like a mechanical watch, but adopts an electronic speed-regulating unit comprising a generator, IC circuit, and crystal oscillator.

In 1999, the Japanese watchmaker introduced two Seiko Spring Drive watches: An 18K yellow gold version with a suggested retail price of 500,000 yen and a stainless steel case model with a suggested retail price of 250,000 yen (both excluding tax) for a limited period. Both belong to the world’s first wristwatch line-up equipped with a Spring Drive mechanism. In the same year, a Credor Spring Drive watch was also launched.

Limited to 500 pieces, the Spring Drive reference SBWA001 watch features a stainless steel case, matching metal bracelet and black dial. The 18K gold Seiko Spring Drive model (reference SBWA002) was limited to 300 pieces. It features a silver dial and crocodile leather strap. Both timepieces are equipped with the Cal. 7R68 Spring Dive manual-winding movement.

Seiko Spring Drive 18K Gold, Reference SBWA002
Seiko Spring Drive 18K Gold, Reference SBWA002

While a general mechanical movement mechanically adjusts the time accuracy, the spring drive Cal. 7R68 utilizes a crystal oscillator (like a quartz watch) for regulating. As a result, the time accuracy of a spring drive watch is within ±15 seconds per month (equivalent to within ±1 second per day), which is comparable to that of a quartz watch.

At 10 o’clock on the dial, there is a power reserve indicator that shows the remaining drive duration. Spring dive watch features smoother sweeping-seconds hand, which is different from ordinary mechanical watches and quartz watches. The spring drive Caliber 7R68 also displays the date function at 3 o’clock. Equipped with 30 jewels, this movement provides a power reserve of 48 hours.

Seiko Spring Drive Stainless Steel, Reference SBWA001
Seiko Spring Drive Stainless Steel, Reference SBWA001

The beautiful movement with the Côtes de Genève pattern and the smooth rotation of the rotor are visible through the see-through case back. Both models were issued in a special luxury box for each type. Inside the box is a plate with a limited edition serial number.

Technical details

Collection: Seiko Spring Drive

Movement
7R68 caliber
Winding method: Hand-wound
Time accuracy: Monthly difference within ± 15 seconds (equivalent to daily difference within ± 1 second)
Power reserve: About 48 hours
Number of jewels: 30
Movement diameter: 29.0 mm
Movement thickness: 3.5mm

Functions
Hour, minute and centre seconds
Date at 3 o’clock
Power reserve indicator

Model: Seiko Spring Drive 18K Gold, Reference SBWA002

Case
18K yellow gold
Glass dual curve sapphire glass with double-sided anti-reflective coating
See-through back (sapphire glass)

Band
Crocodile with 18K yellow gold buckle

Edition
Limited to 300 pieces

Model: Seiko Spring Drive Stainless Steel, Reference SBWA001

Case
Stainless steel
Glass dual curve sapphire glass with double-sided anti-reflective coating
See-through back (inorganic glass)

Band
Stainless steel

Edition
Limited to 500 pieces

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