Vintage Watch | King Seiko 4502-8020 Chronometer Batwing Case

King Seiko 4502-8020 Chronometer: March 1970, 8010 Bat-Wing Case, Near Mint

A King Seiko 4502-8020 Chronometer is a Daini 45KS in the 8010 bat-wing case: manual-wind, 36,000 beats per hour, date, officially certified chronometer. This one is March 1970. The case is brushed on top and mirror-finished on the sides. The gold medallion is intact. Overall condition is close to mint.

What the Seiko Chronometer mark means

King Seiko chronometers of this generation were certified by the Japan Chronometer Inspection Institute (JCII), set up in December 1968, to the old Swiss-style standard. COSC did not yet exist; it was founded in 1973. Early mid-1969 examples that met the tighter AA grade (−3 to +6 seconds a day, the same band as Grand Seiko) were marked Superior Chronometer. From about 1970 the dial and medallion drop “Superior” and read Chronometer Officially Certified — the standard A grade. This 4502-8020 is that later Chronometer. Same 45 movement family. Different grade on the dial.

The Seiko 45 high beat movement

Caliber 4502 is a hand-wound, 25-jewel, 36,000 bph date calibre from Daini. It is the last hand-built King Seiko high-beat; later KS used machine finishing. The 45 series is the production form of the work that put Seiko on the podium at Neuchâtel and Geneva. A 4502 is not itself a contest movement. It is the wristwatch that came out of that programme, adjusted and certified.

Why is the Seiko 8010 bat-wing case special and what is the original condition

Reference Seiko 8010 case: short stubby lugs, flanks that drop sharply, a convex bat-wing or turtle profile rather than the long-lug in other more common 7000 case. About 37 mm across, 42 mm lug-to-lug, 18 mm lugs. On this watch the top is brushed and the sides are mirror. Edges are still there. The gold KS medallion on the caseback is in perfect condition — the part that usually wears off first. Close to mint for a March 1970 steel King Seiko.

Specification

Maker: Seiko

Model: King Seiko 4502-8020 Chronometer

Era: March 1970

Case: 8010 case a rare bat-wing shape, stainless, the top of the case is in brushed top, and side of the watch is in mirror sides, close to mint

Case Diameter: approx. 37 mm

Lug to Lug: approx. 42 mm

Lug Width: 18 mm

Caseback: Gold medallion, in perfect condition

Dial: Perfect condition King Seiko Chronometer Officially Certified 
Movement: Manual-wind Caliber 4502, 25 jewels, 36,000 bph, date, JCII chronometer grade

A March 1970 King Seiko 4502-8020 Chronometer in this case, with the medallion still whole, is the later certified 45KS — not the Superior, and priced as what the dial says.

Shown on a strap. Any colour from our Saddle Series or Kyoto Series on request.