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Discussion Starter · #1 ·
Authored by jason_recliner


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

As far as I can gather, the Crystron divers preceded the first family of Citizen titanium professional divers, which included 300 m, 800 m (AJ0080-08E), and 1300 m models according to an excellent blog by Swingkid ([url=][color=#000000][/url]). Swingkid suggests that the Ti divers were introduced around 1983 so I'm guessing that the Cystron divers were available from the mid-late '70s to 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=][color=#000000][/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 were approximately half the price of the 'Mega' (80,000 yen) so they would not have been base models. Presumably the 600 m models were positioned further upmarket.


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

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


The movement of the Crystron 600 m is the Citizen 8620. I do not know much about this movement except that it has 7 jewels. 7750 posted pics of 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 the clown, the crown can be pulled out two positions, signified as 'clicks'. The first click is for setting of day and date. Turning the crown clockwise sets the day, anti-clockwise sets the date. Both day and 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 engages time adjustmemt. The movement feels okay when setting the time, except that it seems to hit a kind of weak 'resistance' feel to it after a certain number of turns. It's hard to explain, except that it doesn't feel smooth for a bit. By continuing to turn the crown, the weak 'resistance' can be overcome and it doesn't arise again for several more turns of the crown. I don't know if this is standard for the movement, or just a consquence of age and wear.


The case is a stainless steel monocoque design with 19 - 20 mm lugs, a screw down crown, crown guards, and uni-directionalrotating bezel. The bezel appears to be constructed from stainless steel, with a black painted aluminium insert. The upper surfaces of the lugs appear to be brushed, with the case sides, caseback, and bezel polished. My example is covered with hairline scratches and swirlies, however, so the exact original finish is difficult to determine.

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

The caseback has been machined with several concentric circular bevels and layers, presumably to encase the movement with steel of sufficient thickness 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 becameapparent to me when I saw the crystal:



My 600 m came with a black rubber diver strap with two keeper loops, and as far as I know this watch was never offered with a bracelet. The strap is soft and comfortable, and is quite distinctive on the outside, with two rows of moulded block patterns either side of the buckle holes. The underside of the strap has geometric (rectangualar prismatic) indentations not unlike the Seiko 6105 waffle strap,and is signed CITIZEN JAPAN:


The buckle is interesting:


It comprises circular section stainless steel of 2 mm diameter, which has been bent to the required shape. It looks solid, unique, and of high 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) plastic dial with applied indices and applied 'Citizen' and 'CQ' logos. The applied indices have metallic surrounds, but the quality of the indices and surrounds does not appear to be as good as a SBDC001 Sumo. Specifically, the application of lume appears slightly uneven around the 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 the chapter ring. The lume is an unusual bright green colour, similar to the radioactive glow portrayed in cartoons. The prined (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 of design, however, they are a mix of the good, the bad, and the ugly. The sections nearest the centre point are polished metal, with white painted parts beyond. Except for the hour hand, which is all polished metal (apart from the lumed parts).

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

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


The Citizen Crystron 600m diver is a premium quality and interesting alternative to the popular Japanese and Swiss mechanical dive watches from the era, if you can accept strapping a quartz powered piece to your wrist.


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