It was, by all meanings, a discrete watch, by its general allure, with a 34 mm case, its 4, 20 mm height, the sobriety of its dial with no other thing than a minutes and hours hands, and; last but not least, its GREAT movement, the manual winding Cal 849, born in 1994, which qualifies as a very thin one, with a height of 1, 85 mm only. 

I summed in 4 lines all the interest of this watch. 

Though, it was fully appreciated by Connoisseurs, only. 

Is it because of its modest dimensions? Is it because of its remarkable thinness, or because of its very sober dial that this Master Ultra Thin was not that popular? 

I would rather write " thanks to " rather than " because of ". 

First of all, the Master Ultra Thin 34 ( which I will call MUT 34 ) is an example of class. 

We often say " less is more " to describe what is a PuristS' Taste. Here, there is nothing to remove, of course, but most important, nothing to add, either. Would you see a date in such a pure dial? No way! 

Even a second hand? No, please!

I do think that when a watch is well born, it is outstanding, whatever the metal of the case or the color of the dial. 

Here, the other dial of the steel version, in black: 

The MUT 34 existed in rose gold, white gold, steel and platinum. For the rose gold and steel, you had the choice between a black and a silver dial, while the white gold came with a grey dial, and the platinum with a sublime blue dial. Both are great choices, you cannot go wrong with any of them. 

White Gold: 

Platinum: 

Here is another version, in white gold, skeletonized, limited to 75 pieces, issued around 2004: 

Then, it is discretely sophisticated.

Here you have two essential parts which shouldn't be under appreciated: the case, and the movement. 

Better, it is the interaction between the two which makes the sophistication of the MUT 34. 

Here lies the challenge of this watch. 

Do you want an evidence? Did you know that all the Master Ultra Thin are assembled at the Spécialités Horlogères workshop, where all the big complications are made? 

In a 4, 20 mm case, you have to install the glass, the dial, the hands, the movement and the case back... There are few watches which do better, in terms of thinness, such as... Another Jaeger-Lecoutre MUT 39 Jubilé ( 4, 05 mm ), another Master Ultra Thin, the Master Ultra Thin Skeleton Enamel 38 ( 3, 60 mm ). 

The solid case back of the steel case white dialed version: 

The see through case back of the steel case, black dialed version:

Ok, the Cal 849 helps with a height of only 1, 85 mm but still, you only have a bit more than 2 extra mm for the rest...

As for the Cal 849, it is not only thin, it is also beautiful to look at. 

For those who wonder why some prefer manual winding movements to automatic movements, here is a good reason: 

That's the true challenge and value of this watch, a challenge that only the connoisseur can appreciate and fully enjoy. The sobriety ( form ) at the service of the content. 

 And a pretty convincing one! 

So, if you are after a dress watch, with true horological content, without having to sell the house, the MUT 34 is THE watch to seriously consider. 

Looking forward to reading your comments and thoughts,

Best.

Nicolas.