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Authored by: jason_recliner



The Citizen Crystron 600 m dive watch seems to be quite a rarity, andreadily available information is limited. Crystron was a sub-brand fora line of Citizen quartz watches apparently released from the mid-late'70s to the '80s. It was possibly a higher end line, as the 4MHzCalibre 7370 movement of the mid '70s was released under the Crystronlabel. The Crystron range included both analog and digital models.

As far as I can gather, the Crystron divers preceded the first familyof Citizen titanium professional divers, which included 300 m, 800 m(AJ0080-08E), and 1300 m models according to an excellent review bySwingkid ([url=][/url]).Swingkid suggests that the Ti divers were introduced around 1982 so I'mguessing that the Cystron divers were available from the mid-late '70sto the early-mid '80s.

In addition to the 600 m, there were 150 m Crystrons according to a post from 2007 in the GMT +9 blog ([url=][/url]). This is a page from a 1980 Citizen catalog featuring the 150 m divers (image courtesy of GMT +9):


It is worth noting that, at 45,000 yen, the 150 m models wereapproximately half the price of the 'Mega' (80,000 yen) so they wouldnot have been base models. Presumably the 600 m models were positionedfurther upmarket.


In a nutshell, the Crystron 600 m is a quartz analog dive watch withthree hands and day/date. It has a stainless steel monocoque case,uni-directional rotating bezel, and a screw-down crown. My example sitson a rubber strap and as far as I know it was never offered with abracelet.

First impressions upon handling the Crystron 600 m support theconclusions drawn above that this was a relatively (for the Japanese)high end piece and not your average run of the mill dive style sportswatch. When I first held this watch the words that came to mind weresolid, substantial, functional, serious, and quality. For anapproximately 30 year old watch to still be exuding these attibutes isimpressive in my opinion.


The movement of the Crystron 600 m is the Citizen 8620. I do not knowmuch about this movement except that it has 7 jewels. 7750 posted picsof it ( and to me it looks cheaply finished and nothing special:

I imagine that it is a functional movement built down to a price. I know nothing about quartz movements, however.

The movement has day and date, and it hacks. After unscrewing theclown, the crown can be pulled out two positions, signified by'clicks'. The first click is for setting of day and date. Turning thecrown clockwise sets the day, anti-clockwise sets the date. Both dayand date progress with solid, positive clicks, and feel like quality.The day and date wheels appear to be constructed from metal.

Pulling the crown out another click beyond day/date adjustment engagestime adjustmemt. The movement feels okay when setting the time, exceptthat it seems to hit a kind of weak 'resistance' feel to it after acertain number of turns. It's hard to explain, except that it doesn'tfeel smooth for a bit. By continuing to turn the crown, the weak'resistance' can be overcome and it doesn't arise again for severalmore turns of the crown. I don't know if this is standard for themovement, or just a consquence of age and wear.


The case is a stainless steel monocoque design 42-43 mm wide (excludingcrown) with 19 - 20 mm lugs, a screw down crown, crown guards, anduni-directional rotating bezel. The bezel appears to be constructedfrom stainless steel, with a black painted aluminium insert. The uppersurfaces of the lugs appear to be brushed, with the case sides,caseback, and bezel polished. My example is covered with hairlinescratches and swirlies, however, so the exact original finish isdifficult to determine.

The case definitely imparts a sense of robustness, longevity andquality. Apart from the considerable heft, the bezel rotates quitestiffly with firm, well defined clicks, and the large crown screws downsmoothly onto a thick stem:

The caseback has been machined with several concentric circular bevelsand layers, presumably to encase the movement with steel of sufficientthickness while avoiding excess material:


The case back carries the text (clockwise):



All Stainless Steel
4-860756 y


7750 dismantled one of these, and the quality of construction became apparent to me when I saw the crystal:



My 600 m came with the original black rubber diver strap with twokeeper loops, and as far as I know this watch was never offered with abracelet. The strap is soft and comfortable, and is quite distinctiveon the outside, with two rows of moulded block patterns either side ofthe buckle holes. The underside of the strap has geometric (rectangularprismatic) indentations not unlike the Seiko 6105 waffle strap, and issigned CITIZEN JAPAN:


The buckle is interesting:


It comprises circular section stainless steel of 2 mm diameter, whichhas been bent to the required shape. It looks solid, unique, and ofhigh quality. The buckle tongue, by comparison, is nothing special.

[b]Dial, Hands, and Text[/b]

Note that the following observations were made without access to a loupe.

The dial of this watch appears to be a basic black (dark grey) plasticdial with applied indices and applied 'Citizen' and 'CQ' logos. Theapplied indices have metallic surrounds, but the quality of the indicesand surrounds does not appear to be as good as a SBDC001 Sumo.Specifically, the application of lume appears slightly uneven aroundthe edges of the indices.

The quality of the 'Citizen' and 'CQ' logo appliques, and the dial work in general, is excellent:


The hour indices are all lumed, as well as a lume dot at 12 on thechapter ring. The lume is an unusual bright green colour, similar tothe radioactive glow portrayed in cartoons. The printed (plastic?)chapter ring, as well as minute marks, includes a lumed dot at 12.

The 600 m hands, in terms of material quality, are superb. In terms ofdesign, however, they are a mix of the good, the bad, and the ugly. Thesections nearest the centre point are polished metal, with whitepainted parts beyond. Except for the hour hand, which is all polishedmetal (apart from the lumed sections).

The seconds hand is sensational, being a Sinn like box of lume on adelicate stick. 10/10. The minutes hand is an unispired pointer. Andthe hours hand is a Mercedes logo. Enough said!

Several text fonts and sizes were utilised on the dial and bezelinsert. The bezel insert font is bold and angular, like the fontutilised for college football jersey numbers. Printing on the dialishigh quality, silver/grey. and in a generally nondescript font.


The Citizen Crystron 600m diver is a premium quality and interestingalternative to the popular Japanese and Swiss mechanical dive watchesfrom the era, if you can accept strapping a quartz powered piece toyour wrist.


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