King Seiko Hi-Beat 5625-7000 – Caliber 5625A, Suwa Seikosha – Stainless steel, date only – March 1971 – freshly serviced

No day of the week. Just a date window at three o'clock.

That might sound like less, but for many collectors, it’s the deciding factor: a single window hardly disrupts the symmetry of the dial, whereas a day and date side-by-side create a wide block that dominates the right half of the dial. Anyone who appreciates the reduced design of the King Seiko will find it most consistently implemented in the 5625.

King Seiko – the line from the other factory

For decades, Seiko maintained two completely separate production facilities that competed against each other: Suwa Seikosha in Nagano Prefecture and Daini Seikosha in Tokyo. Both developed their own movements, maintained their own model lines, and vied for the top position. Corporate management explicitly encouraged this—whoever built the better movement received the order.

In 1960, Suwa introduced the first Grand Seiko. Daini responded in 1961 with the first King Seiko. What followed is one of the most productive rivalries in watchmaking history: the 44KS in 1964, the 45KS with 36,000 beats per hour in 1968, and in parallel, the 52 series from Tokyo.

With the 56 series, the situation reversed. The calibers 5625 and 5626 originated from Suwa—the same factory that built Grand Seiko. Suwa thus supplied both the Grand Seiko and, under the King Seiko name, its direct in-house competition. The Grand Seiko caliber 5646 and this King Seiko caliber 5625 share the same basic architecture; they were distinguished by fine adjustment, features, and finishing.

King Seiko was therefore never the second choice, but rather the more affordable watch with the same structural foundation.

"Hi-Beat" – what’s on the dial

The inscription KS HI-BEAT refers to the high oscillation frequency of the movement: 28,800 semi-oscillations per hour, meaning eight vibrations of the balance wheel per second.

The logic behind this is simple. The faster a balance wheel oscillates, the less external disturbances—shocks, changes in position, accelerations while wearing—affect the rate. A fast-oscillating balance returns to its rhythm more quickly. The price is higher wear and a more sophisticated construction, which is why Hi-Beat movements were installed exclusively in top lines at the time of their introduction.

This is visible in the seconds hand: it runs noticeably smoother than in a movement with 18,000 or 21,600 semi-oscillations.

The 5625A caliber

• Automatic with additional manual winding
• Hacking seconds when the crown is pulled out – for setting the time to the exact second
• 25 jewels, 28,800 semi-oscillations per hour
• Date with quick-set, no day of the week display
• Manufactured by Suwa Seikosha, Japan

The 5625 is the date variant of the same movement family from which the 5626 with day and date originates. Less calendar mechanism means fewer moving parts and a slightly flatter movement—this watch measures 9.7 mm in height compared to around 10.5 mm for the day-date models.

Removing the movement from the front – and a turning point in the fine print

The case back bears the instruction OPEN THRU GLASS, PUSH SET LEVER, PULL STEM. The movement is not removed from the back, but from the front through the removed crystal; the addition is intended for the watchmaker because the setting lever must be pressed before the winding stem can be pulled.

The structural reason for this is water resistance: a case that is not opened from the back has one less weak point.

What is written next to it is interesting. The identical cases from the years 1968 to 1969 were stamped "WATERPROOF". This specimen from 1971 bears "WATER RESISTANT"—despite an identical construction.

The reason lies not in the technology, but in the law: around 1970, the labeling of water resistance was internationally re-regulated, and absolute phrases like "waterproof" disappeared from catalogs. At the same time, Citizen replaced the brand name "Parawater" with "Water Resistant". This watch thus visibly stands on the other side of this turning point—and the lettering confirms the dating to 1971 independently of the serial number.

Dial and case

The dial is executed in a light silver tone with a fine radial sunburst finish, which travels across the surface from the center to the outside as light changes. The hour markers are applied, multi-faceted batons with sharp edges and deep black-contrasted flanks; executed as a double index at twelve o'clock. This is complemented by slender polished hands and a fine center seconds hand.

The dial is sparsely inscribed: SEIKO AUTOMATIC to the left of the center, KS HI-BEAT with the Suwa symbol to the right. The date window at three o'clock is framed by an applied border.

The stainless steel case follows the design language that Taro Tanaka formulated at Seiko as the "Grammar of Design": flat, sharply defined surfaces instead of rounded transitions, angular and elongated lugs, and a flat bezel. Tanaka's principle was that each surface should reflect light in a defined direction—which only works as long as the edges remain crisp.

With a diameter of 36.9 mm, 41.8 mm lug-to-lug, and only 9.7 mm in height, this watch is one of the flatter King Seikos and wears correspondingly unobtrusively.

Condition

First, what you need to know: The gold medallion on the case back is missing. The circular receptacle in the center of the case back is present, but the insert with the KS emblem is not. This is not an uncommon finding for these models—the medallions are set in rather than screwed on, and over five decades and multiple services, they are regularly lost. Nothing of this is visible on the wrist; however, anyone looking for a King Seiko with an intact medallion should choose a different specimen.

Technically, the watch is flawless. It was professionally serviced in Japan in the spring/summer of 2026—fully disassembled, cleaned, oiled, and regulated. Automatic winding, manual winding, hacking seconds, and the quick-set for the date function perfectly.

The dial is well preserved: the sunburst finish runs evenly throughout, the lettering is complete and sharp, the applied indices are firm and show no corrosion, and the date frame is intact.

The stainless steel case shows age-appropriate signs of wear, more noticeably in places on the bezel edge and the flanks of the lugs. The surface transitions are preserved; the watch has not been over-polished. All case back engravings—reference 5625-7000, serial number 131490, workshop instructions—are complete and clearly legible. The crystal has slight signs of use.

A new Seiko leather strap is fitted.

Technical specifications

• Brand / Line: King Seiko, Hi-Beat
• Reference: 5625-7000
• Serial number: 131490
• Production date: March 1971
• Movement: Seiko caliber 5625A, automatic with manual winding, 25 jewels, 28,800 vph, hacking seconds
• Manufacturer: Suwa Seikosha, Japan
• Functions: Hours, minutes, center seconds, date with quick-set
• Case: Stainless steel, movement removed from the front through the crystal, gold medallion on the back is missing
• Diameter (without crown): 36.9 mm
• Height: 9.7 mm
• Lug-to-lug: 41.8 mm
• Lug width: 18 mm
• Weight (incl. strap): 47 g
• Strap: New Seiko leather strap
• Crystal: Acrylic glass
• Service: Spring/summer 2026, Japan – full disassembly, cleaning, oiling, regulation

For whom

For anyone who wants a date, but not a day of the week. A single window makes the dial appear calmer than the wide double block of the day-date models—and the 5625 is the more purist version within the King Seiko line. The missing medallion on the back makes it significantly more accessible than comparably preserved specimens.

For collectors who want to map the Suwa side of Seiko history: this movement shares the basic architecture with the Grand Seiko caliber 5646 from the same production facility.

And for anyone looking for a flat automatic watch for every day. 9.7 mm height at 41.8 mm lug-to-lug and 47 g—that disappears under a shirt sleeve, and after the service, the mechanism runs again exactly as intended in 1971.

Warranty (used)
This is a used item. The statute of limitations for claims for defects (statutory warranty) is 12 months from delivery.

Note
As this is a vintage watch, water resistance cannot be guaranteed. To protect the movement, the watch should not come into contact with water or moisture.