At some time in the sixties Taro Tanaka, Seikos first hired graduate of a College Design Program, came up with design rules which eventually came to be known as the Grammar of Design at Seiko. He wanted Grand Seiko and King Seiko watches to sparkle brilliantly when on display and without any distortions.
The rules were simplicity itself:
1. Perfectly flat surfaces and angles for cases, dials, hands, indexes
2. Two Dimensional faceted curves for the bezel
3. All distortion should be eliminated from the dial, hands, indexes and case, the finishing of the dial and case should be a mirror finish so it shines and sparkles
4. No more round cases, a unique case design
Those looking for the most valuable King Seiko should look for a mid to late sixties Daini or Suwa release like the King Seiko 5626-7000. (Case and dial design sparkling from all angles). In all its aspects Tanaka's design is so iconic that all Seiko products that were released afterward emulated it. Still, there was plenty of room for other quircky designs like the cushion case or the folded GS. The 5621 time only is a nice example of that, especially with its appliqué roman numerals and its special roman four - go check it out.
The Daini designs never had gold medallions. The Suwa King Seikos then, with medallions, were produced actually for a rather short period, until early 1972.
Interestingly, there is some lug variation in individual examples of these watches in the relative width of the side surfaces and of the very narrow flat surfaces on the inside top that does not appear to be due to refinishing. Also, in 1971 Seiko undertook a major redesign of the case and dial of the standard KS 5626-7000, resulting in the 5626-7110 on sale here.
The ultimate King Seiko
Later production runs of this 5626-7110 and the 5626-7040 chronometer, while keeping the monobloc case designs and case numbers, lost the medallion, substituting an engraved KS roundel instead. Pity the poor Japanese businessman, who, probably sometime in 1972, was gifted a later example 5626-7111 or 5626-7041 as a retirement present and discovered that it lacked the coveted gold medallion!
The basic case and dial design of the 5626-7110 was retained for all of the standard 562x King Seikos produced until 1975, although there were a number of minor changes made, designated with new case numbers.
By far the biggest change (in late 1972) was from the 5626-7110 to the 5626-7111, when the one-piece monobloc case was abandoned in favor of a screw-back design. Even then some 7110s were produced with this new design. The case is otherwise practically identical, although in side profile the top surfaces of the lugs slope very slightly less far down, and the side surfaces are correspondingly a little wider. The movement was also changed slightly to replace the external regulator with a standard one, with this designated by a B on the rotor (5626B) instead of an A as on the externally regulated version. At the same time, the 5626-7040 chronometer was replaced with the 5626-7041, also a screw-back design and also otherwise nearly identical to the previous monobloc model, with the same case-back font style as the standard KS 5626-7111.
The end of the line
In the following year, 1973, the case number for the standard KS was changed again, resulting in the 5626-7113. This watch was produced from 1973 all of the way through until the end of the line in 1975.
With the 5626-7113, the Seiko KS in large letters on the case-back is replaced with a simple Seiko in smaller letters, the ultimate end-point of the trend in the 1970s away from decorative case-backs towards a simple, industrial style. The signed crown on the 5626-7113 is slightly different from the one on the 5626-7110, with most 5626-7111s seemingly having the 5626-7113 type(?) perhaps the change in the crown design occurred during the 5626-7111 production run, and of course this is a part that is often swapped in old watches or may even have varied in new ones depending on parts availability at the factory.