Review: Blancpain New Classic Ultra Slim Reference 2021-3630-55


Blancpain is said to be one of the oldest watch companies in the world. Originally it was founded in 1735 by Jehan-Jacques Blancpain, as you can see it in its dial. Unlike its honorary record, Blancpain is not an eye-catching brand very much such as Omega, IWC and Rolex. Rather than that, Blancpain is well known as a luxury watch brand by limited die-hard fans. That also should be expected, Blancpain is a member of Swatch Group and it is positioned as the highest range in Swatch Group lineup. Additionally, you might have also known that Vladimir Putin is a big fan of Blancpain.

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What is the best collection in Blancpain? You may answer “That has to be Fifty Fathoms.” Yes, Fifty Fathoms is famous and popular as the first dive watch (second one is well-known dive watch Submariner by Rolex), and even great with no doubt. However I have been wondering that Blancpain, its qualification actually can be seen in classic collections. That is the reason why I believe New Classic Ultra Slim should be the first review on this website.

Overview – Blancpain New Classic Ultra Slim

New Classic is one of the most terrific collection by Blancpain. It seemed to be produced around 1990s-2000s and nowadays it is already discontinued unfortunately. New Classic had many variations in different case material, dial design and function. This Ref. 2021-3630-55 has black dial and red gold case and it only exists 300 pieces all over the world as a limited collection in 1999.

Having just two hands (hour/minute) with crocodile leather strap, 2021-3630-55 looks quite classic. Rose gold double stepped (double pomme) bezel and thin case even highlight it. More than anything, Breguet arabic numerals make it extremely elegant and even a little bit coquettish.


The whole case is made of rose gold, again. Like you may have known, the name of gold cases are categorized by the composition.

Sourced by h-tokeiho

Nowadays many brands are more likely to use pink gold or yellow gold than red gold, Blancpain is the one who tends to use red gold. In my opinion, red gold case goes pretty well with black dial so it is literally a fantastic point of this limited watch.

Case diameter is approximately 36mm. With thinking that this is a thin classic watch which has just two hands, around 35mm would be the best size. Thanks to the short lugs, Lug to Lug height is about 40mm, which is also good size.

Nowadays we have a lot of classic design watches which are around 40mm case diameter but most of them have a lack of proportion. In other words, the appropriate case diameter should be decided by whole components’ balance on the dial, not by the latest craze.

Comparison with modern watch – FC-306MC4S36. 36mm diameter looks better to make the design concentrated.

Needless to say, it is really important to consider case thickness for classic watches. Especially dress watches have to go with your cuffs, shirt and suit. Too thick watch may make you look dull. With this watch, the case thickness is only 6.2mm. As Blancpain is well known as a marvelous watch maker especially in thin watches, New Classic Ultra Slim is still competitive against modern thin watches.

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The lugs have through holes for spring bars, which leads to easier strap changing without little damages against lugs. By the way, I wonder why I have not seen through holes on modern watches recently…maybe because of their looks?


Because of manual winding watches, you need to wind this watch every single day. This crown, which can be moved literally smooth may make you feel better. Such kind of comfortable feeling should be needed especially for luxury watches, I am pretty sure.

Looking at the crown from the backside – I should describe it as a “triple stepped” case?

Dial – Indices and Hands

When it comes to considering Blancpain’s dial, I guess Opaline dial is the most famous. Additionally, Blancpain has also been using “Grand Feu” enamel recently. On the other hand, this watch has a matte finished black dial, which was created in the late 1990s.

Blancpain Logo.

Applied indices can be seen beautifully on that black dial. 3, 6, 9, 12 are highlighted by Arabic numerals, others are shown by dagger indices. As you can see, Arabic numerals are not just normal, but so-called Breguet numerals. Those coquettish style of applied indices are definitely the excellent part of this watch.

These indices led me to fall in love with this watch. These indices are literally showing what “three dimensional” is. Similar feeling with URBAN JÜRGENSEN Ref.8-big.

The hands are looking very linear design in comparison with Arabic numeral indices. These differences provide a good contrast.


Buckle is also made of red gold as same as its case along with brand name engraving. Buckle width is 16mm and lugs width is 19mm with normal spring bar system, so you can change it as you like. In this picture, I have already changed a brown crocodile strap from the original black crocodile.

Case Back – Movement

Blancpain Caliber 21 – really fantastic looks.

New Classic Ultra Slim has a transparent case back as some of other Blancpain’s watch does. Well-finished Blancpain Caliber 21 movement based on Frederic Piguet 21 which is quite famous caliber as long-life, thin movement.

<Blancpain Caliber.21>

  • System – Manual (hours and minutes)
  • Diameter – 20.4mm
  • Thickness – 1.73mm
  • Jewels – 18
  • Power reserve in hours – 42
  • Frequency – 21,600 A/h (3Hz)
  • Note – Based on Frederic Piguet Caliber.21

Blancpain Cal.21 is based on Piguet 21, which was used by Cartier, Chopard and Bucherer. Frederic Piguet had provided this Piguet 21 as Ebauche for Blancpain Cal.21 and even Patek Philippe Cal.175 and 177.

Piguet 21 is a really terrific movement. It was boned in 1925 as the thinnest watch movement – originally only 1.75mm thickness with 18,000 A/h frequency. Until AP 2003 was unveiled, Piguet 21 retained the thinnest record over 20 years.

Even without the thinnest record, Piguet 21 still had been used with some small modifications. The later version has 1.73mm thickness with 21,600 A/h.

The good feature of this movement is not only its thickness. Its well developed, old school, attractive appearance makes us impressed so much.

Kif shock protection is installed.

Nowadays, I know the thickness is not the only point to judge if the watch movement is good or not. However, I am simply impressed by the fact that Piguet 21 had been produced and loved over 90 years without big modification. Besides, its thickness is still very competitive against modern movements.


Great looking and meaningful watch with a great history, well-designed movement.

It is difficult to see such a concentrated and coquettish design in modern watches, even in dress watches of Blancpain’s current lineup. Though it is hard to come by and not recognizable so much that other famous watches, it definitely worth to get if you feel something fabulous from it.

While winding this watch, I am wondering if Blancpain unveils this kind of watch again.

Overall Rate 4.3

The video this watch shows up

Spec Information

  • Brand: Blancpain
  • Model: New Classic Ultraslim Limited Edition
  • Reference: 2021-3630-55
  • Movement: Blancpain Cal.21 (Based on Frederic Piguet Cal.21)
  • Remarks: Limited 300 pieces, Discontinued
  • Expected List Price: 1,210,000 JPY
  • Weight: 48g