Review: Citizen AQ 6010-06A Caliber 0100: the most accurate watch in the world

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Citizen is the brand to beat in the race for the most accurate watch in the world. Of course, we limit this race to only watches which are not connected, and keep the timing within the watch. GPS or radio controlled watches can keep to atomic clock accuracy, but the timekeeping is referenced externally. Currently, the Citizen 0100 is the most accurate watch in the world. By a large margin.

The flagship model is theAQ6010-06A ,18K in white gold, Limited edition of 100.

The pursuit of accuracy

The pursuit of accuracy is one aspect of horology which is fascinating. Of course, traditional haute horlogerie is not absolutely consumed by this goal, pursuing instead the hand workmanship and finishing details, or with the fascination on making complicated indications available on a mechanical watch. Typically, in a haute horlogerie watch, the game stops at getting it accurate enough. And this is defined by COSC which certifies watches achieving −4/+6s a day for mechanical devices, and ±0.07s a day for quartz timepieces. And for Rolex, this standard is tighter for their Chronometer certified mechanical watches – +/-2s a day.

We first saw the Caliber 0100 shown as a prototype in a gorgeous sapphire crystal case in pocket watch form last year in Baselworld 2018.

So how much accuracy is enough? Practically COSC is good enough, But the proper engineering answer is the same as the answer to the question – how long is a piece of string? And being a company totally rooted in engineering and pursuing the limits, Citizen’s current best answer is the Caliber 0100 with a variance of 1s a year. Although we believe, they will continue to push the limits even further. In fact, we do know that their engineers are already working at improving this as we speak. While all the competition (Longines Conquest V.H.P.), and Citizen’s own next best is only able to offer a maximum variance of 5s a year, and most others only meeting COSC standards are at 2s a month. As a comparison to the other Japanese watchmaker, the Grand Seiko 9F movement is rated only to 10s a year.

Take a moment to reflect on the precision needed for a maximum variance of 1 second every year. This is a maximum error of 1 part every 31,557,600.

The Citizen AQ 6010-06A

The Citizen Caliber 0100 is offered in three variants. All limited editions. The flagship model is in a white gold case delivered with a crocodile strap, and a stately, pristine, austere perhaps, but magnificently beautiful white dial. Two other versions in the Citizen Super Titanium (Duratect α) case and bracelet is offered in either a mother of pearl dial, or a black lacquer dial.

In a dark MOP dial, the AQ6020-53X, Super Titanium (Duratect α) case and bracelet is limited to 200 pieces.

The case, dial and hands

We focus on the white gold flagship model, and other than case material, dial and bracelet, they are the same. The same Caliber 0100 is within the watches. The case measures 37,5mm in diameter and a thickness of 9.1mm, with a water resistance rated to 50m.

The design is almost austere, but exudes elegance. And a restraint that is derived from a century of good breeding.

The austerity of the design and the simplicity speaks of restraint. One which comes from a century of good breeding and class. The case finishing is outstanding, with highly polished parts which are angular to emphasize the structure of the quartz crystal.

While not ultra thin, the watch is slim enough tat 9.1mm thick on a case the diameter of 37.5mm

The dial itself is a light ivory, tending on white. And is marked by printed line markers for each second, punctuated by larger shaped, chamfered applied indices. These indices are stepped to ensure that it catches light in many directions, and finished zaratsu style. The indices are tipped with SuperLuminova.

The second hand is rather long, reaching almost the the edge of the markers, and as this is a quartz watch, with precise jumps between markers. These jumps of the second hand is excuted in perfect alignment to each marker. The end of the hand is ever slightly bent by hand to reduce parallax error.

From any angle, the case, dial and hands are a perfect unity of form meets function.

The minute and hour hands are also long and is made of rather heavy brass. This is done intentionally. And as the brass hands are heavier than traditional ones, Citizen uses specially designed and manufactured high torque motors to run them.

The movement: Caliber 0100

The star of this show is definitely the movement. The Caliber 0100 is an engineering feat like no other. The accuracy achieved is spectacular and the raison d’être. The finishing is lavish, almost like a high end mechanical offering. The plates are finished in a blackened ruthenium plate, which gives it a high resistance to corrosion and dis-colouration.

The open case back with double sided anti reflective coating, showing the Caliber 0100.

The details of the movement is outlined in our Press Release article, and I highly recommend you give it a read here. In a jist, other than the super accuracy, the movement is Citizen’s Eco-Drive, meaning that it is powered by light, with a running time of 6 months on a full charge, and 8 months in power saving mode.

The competitive landscape

In the world of the 1s/year accuracy, there is only one king. Or Emperor, in respect to the Japanese crown. And he is the Caliber 0100. All three novelties discussed here have no other competition but themselves.

For me, my pick is the white gold model. The purity of the metal, of the light ivory dial, and the simplicity of the hands and markers just make it super compelling. While it is true that US$ 16,800 is a high ransom for a quartz watch, but what is the price of the most refined engineering wrapped in a case and dial which is superbly hand made. See our report on the Citizen Manufacture for the story of how the high end pieces are hand made, while the mass production models are made in a ultra high speed robotic line.

And the AQ6021-51E, has a black laquer dial in a case and bracelet made of Super Titanium (Duratect α), Limited edition 500 pieces.

But for others who are fascinated only by the movement, the next best option in my view, is the one with the dark mother of pearl dial. The pearlescent dial radiates, and while dark, still allows sufficient light to charge the Eco-Drive movement. The bracelet is also rather comfortable and elegant in design.

In a lower hierarchy, the Citizen AQ4020 offers an interesting alternative at a significant lower price of ¥ 330,000 excl Japanese VAT (approx US$ 3,300). Also in Duratec α Super Titanium case and bracelet, it adds the hand made washi paper dial, with a perpetual calendar thrown in. Or the Longines Conquest V.H.P. at an even lower price offers entry into high precision watches. Build quality is more mass production than either Citizen, but the price is commensurate at only S$ 1,510. Both the AQ4020 and the Conquest V.H.P. offer 5s/year precision.

Concluding thoughts

I love the Citizen AQ6010-06A for everything it represents. High precision engineering resulting in superlative accuracy. Beautiful, restrained Japanese styled aesthetics, which is simple, elegant and as mentioned reeks of class which can only result in a century of excellent breeding.

Elegant and beautiful as a dress watch on the wrist.

The watch looks beautiful. And promises to perform beautifully over the long term. We have not had the watch to go through daily tasks but if we go by the AQ4020 which we had on hand for about 3 months, it is going to be flawless.

There is perhaps also no reason why Citizen might not add further references to carry the Caliber 0100, I supposed only limited in the difficulty to manufacture and the skill to assemble and adjust. So maybe, we will see more watches with this amazing accuracy. Or perhaps the filter down effect might take place, and we will see the 5s/year movements moving downstream in the Citizen lineup while the top of the line is the C.0100. By the way, these watches will be offered worldwide, instead of only in Japan for the AQ4020. In Japan, the new Caliber 0100 range will be offered in The Citizen line with the 10 warranty program.



  1. Missed a key word: * if it vibrates at 1 Hz off in those 8,388,608 Hz it’ll be 1.6 seconds off in a year.

  2. Love it. However “I supposed only limited in the difficulty to manufacture and the skill to assemble and adjust” What kind of adjustment are you referring to? Aligning the hands with the markers when mounting the hands over the dial? The adjustment with regard to keeping time, once the watch is assembled, is 100% software driven, compensating for temperature and aging mainly. Another major hurdle in construction and software, is making it frugal enough to be driven by light only. This even more impressive. It vibrates at 8,388,608 Hz. To translate the max 1 second error in a year into Hz, if it vibrates at 1 Hz in those 8,388,608 Hz it’ll be 1.6 seconds off in a year. 0.5 Hz wrong equals just under .8 seconds… What precision!