Seiko KS Chronometer Hi-Beat Ref. 5625-7040 - Officially Certified
Seiko's engineering pinnacle in the early 1970s took place not only in the Grand Seiko laboratories but also under the umbrella of King Seiko (KS). The Ref. 5625-7040 is a quiet yet majestic representative of this pinnacle: it is one of the rare Japanese models to be certified as "Chronometer Officially Certified" by Seiko, certifying that it has passed accuracy tests equivalent to the Swiss COSC standard.
With a stainless steel case measuring just 10 mm thick, this model embodies Seiko's response to the "high-frequency precision race" of the era. Inside, the 5625A Hi-Beat caliber, a movement beating at 28,800 beats per minute and featuring Seiko's signature "chronometer-grade" setting, makes this watch more than just a KS; it's equipped with one of the few pre-1970 Seiko calibers certified as chronometers. The anthracite-gray sunburst texture on the dial features a finely lined surface treatment that reflects light from every angle. The sharpness of the minimalist indices and the polished facets of the hands clearly demonstrate the level of craftsmanship applied at Seiko's Daini factory.
The 14-karat gold "KS medallion" on the case back is a badge of honor worn only on official Chronometer series. This gold emblem symbolizes both the purity of the model and the high-class manufacturing tradition of the era.
Technical Specifications
Ref: 5625-7040
Serial No: 038799
Manufactured: March 1970 - Japan
Caliber: Seiko 5625A, self-winding, 25-jewel Hi-Beat (28,800 bph), date complication, "Chronometer-grade" setting
Case: Stainless steel, 10 mm thick
Glass: Dome-shaped crystal
Dial: Anthracite sunburst finish, thin baton indices, date window at 3 o'clock
Crown: Original "KS" logo
Case back: 14-karat gold Seiko KS Chronometer medallion, fully hallmarked
Strap: Olive-grey genuine leather (new)
Box: Seiko box included
Condition Report
The case has been preserved with its factory brushed finish.
The dial and hand set are in excellent condition; all inscriptions are clear, and the indices are luminous. The crown and case back are completely original.
The movement is clean, keeps time reliably, and maintains a consistent Hi-Beat vibration.
Evaluation
The 5625-7040 is one of the rare models where Seiko has made the Chronometer standard not just a document but an engineering commitment.
The 14-karat gold medallion on the case back symbolizes this status.
It is considered one of the most refined King Seiko references in the collection, representing the Japanese precision of the 1970s with the spirit of pre-Grand Seiko.
The product you are viewing was manufactured in 1970.
Professionally overhauled and FULLY SERVICED (the movement is completely disassembled, its components cleaned, oiled, and adjusted), your watch will function flawlessly without any surprises. (It will be maintenance-free for 3 years unless exposed to direct water or high humidity for extended periods.)
Item Condition: Tested, fully functional, and in working order.
