Seiko developed a movement based on the Seikosa Daini 54A that did not bear any serial number for their 1961 luxury King Seiko. Later the movement got some tweaks and was named calibre 44 They also added added a date complication with a reworked date plate known as the 4402 and a chronometer speck with two extra jewels.
King Seiko cal XX-4420
- Made approximately: 1961-1968
- Made in Japan
- Power reserve 46h
- Jewels
- 18000 B/A
- Lift angle 52°
- DM XXmm
- H XXmm
King Seiko calibre XX-4402.
Surface finish is of high quality. All screws are highly polished to a decent finish. The bridges are nicely finished with rhodium plating, but with yellow varnish in lettering rather than gilt. Impressive 25 jewels + 2 on the chronometer. Ratchet wheel has a impressive design and finish.
Top surface finish on plates: 7 Points
Surface finish on screws: 7 Points
Surface finish on ratchet and ratchet wheel: 9 Points
Movement jeweling: 9-10 Points
The movement was fairly modern for 1961
Movement innovation standard (for 1961): 7 points
The Seiko base plate has a decent finish. Winding, date and setting mechanism have an acceptable finish. Gear train has a good finish. Winding and setting feels nicely balanced.
Base plate finish: 5 Points
Setting and winding mechanism: 7 Points
Date change snappiness: 7 Points*
Gear train finish: 7 Points
Movement durability: 8 Points
A very nice bonus feature on the Seiko KS is the quick-set date function; easy to use and well engineered.
3 extra bonus points
+ 2 bonus points for extensive and modern reworking of base plate
Total 5 points*
A quality feature that I always appreciate is a hacking lever.
3 extra bonus points *
Balance bridge is of a very nice design with a nifty micro regulator and adjustable boot regulator
4 Extra bonus points
Chronometer version has 2 additional jewels and more balance adjustment at factory +2 points*
The Seiko movement in question was very accurate and keeping close to COSC time during testing, even after 50 years.
Accuracy: 8 points
Power reserve of 46 hours is good.
Power reserve: 8 Points
King seiko XX-4402 points:
Surface finish on bridges and top side of base plate: 7
Surface finish screws: 7
Surface finish on ratchet and ratchet wheel: 9
Movement Jeweling: 9-10*
Movement innovative design for ca 1961: 7
Base plate finish: 5
Setting and winding mechanism: 7
Date change snappiness: 7*
Gear-train finish: 7
Movement durability: 8
Total bonus points: 4-14*
Accuracy: 8
Power reserve: 8
Grand total: 91-107*
*Bonus points and date version.