The X8 Cosmotron production run was short, about 10 years in all, since the early 1970s saw the quartz revolution, and older technology was quickly rendered obsolete. However, there was significant development of the technology during its brief history, including raising the beat rate from a conventional 18,000bph at the start to 43,200bph at the end, in those using a relatively conventional balance. The quality of the X8 movement was indicated by its achievement of chronometer standards. This reflects the aims of the electronic technology to increase both reliability and accuracy, both of which were overtaken by the advantages of quartz modules.
In March of 1966 Citizen presents the 'X-8 Cosmotron' with spring balance and transistor. The X-8 was a watch with four magnets on the balance and two fixed coils. Movements like cal. 0802, 0820, 0884, 0840, 0880 and 4840 were even sold to about twenty foreign companies including Bulova, who manufactured complete watches under their own name. Citizen itself was faced with strong competition from the cheaper Seiko-Electronic EL 3300.
Launched in 1967 with 12 jewels and beating at 6 beats per second (21600 bph), this Citizen was produced for 5 years only. While the 4840 caliber is almost the same as the 0840 before that, the X8 for the first time had a date complication.
This particular rare blue dialed watch is from 1971, note the bracelet / strap types and case numbers for the different case designs, to wit cushion or with protruding lugs.
1972 saw the launch of new models with both date and day complications, now using the 78 movement. With jewelling reduced to 8, and now powered by 1.3v silver oxide batteries, the movement design had been refined, with more functions. The rate increased to 36,000bph, and movements were designated 7801A, 7802A, 7803A, 7804A and 7806A. The X8 name had been dropped, so dials are marked Cosmotron, Electronic and carry the Cosmotron applied logo.