Introducing: The Tefnut Twist, A New Take On Winding A Watch From Moritz Grossmann

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One of the nicest things about doing trade shows like Baselworld is that occasionally you come across a fresh idea, which in watchmaking is a lot harder than you might think. After all mechanical horology is nothing if not an exercise in technical incrementalism. Thomas Mudge made the first watch with a lever escapement in the mid-18th century, and if you were to show him a modern automatic wristwatch, he might have a couple of questions about metallurgy, and he’d probably get pretty excited about the lubricants, but there’s nothing he wouldn’t fundamentally recognize. 

Which is why I got a kick out of the Tefnut Twist. The innovation in the Tefnut Twist isn’t going to rouse the ghosts of Breguet and Harrison but it’s quite original all the same. In watchmaking there are very few really new ideas at any given time but I can’t recall ever seeing anything quite like this before.

moritz grossmann tefnut twist

The Tefnut Twist "Classic" in white gold.

As you can probably see from the top picture the Twist quite literally has an unusual twist in its construction: you wind the watch by turning the strap back and forth. The lower strap attaches to a cylindrical lug that penetrates the case, and as you twist the strap back and forth, a ratchet wheel in the movement rotates, winding the mainspring.

Moritz Grossmann caliber 102.2.

Moritz Grossmann caliber 102.2.

The caliber 102.2 contains a special click wheel system designed to prevent excessive tension in the mainspring.

The caliber 102.2 contains a special click wheel system designed to prevent excessive tension in the mainspring.

The movement is caliber 102.2, which is 26 mm in diameter – a little small in the context of a lot of movement design in the last decade, but not especially diminutive (that’s about the diameter of an ETA 2892-A2). The balance is made in-house by Grossmann, (as is most of the rest of the movement; the short list of supplied components includes a Nivarox balance spring) and there’s a 48 hour power reserve. If you look closely, you’ll see that the ratchet wheel is a bit unusual – there are only eight teeth. This means that the wheel has to turn through a fairly large degree of arc before the click (the spring-loaded pawl just above "19 Steine") engages. The idea here is to prevent the watch from constantly being wound by the small movements of the strap when the watch is on the wrist; with this set-up, the strap has to be turned through a minimum of 20 degrees of rotation in order for the click/pawl to engage.

In addition, the spring has a slipping bridle, which is a feature of all self-winding movements; the slipping bridle holds the outermost coil of the mainspring in place in the barrel, by friction; however, if tension gets too high the bridle will slip, relieving excess pressure. 

The Tefnut Twist does have a crown, but it’s used only for hand-setting; there’s a stop seconds mechanism as well. Though small, the movement is a very, very pretty piece of work with as much attention to detail as we’ve gotten used to from Grossmann in its other movements, and both its mechanical engineering, and finish, go a long way towards making the Twist a standout.

The Tefnut Twist "Fancy" model in rose gold.

The Tefnut Twist "Fancy" model in rose gold.

At launch, there will be three models in two variations each; the Classic, Fancy, and Gent, with each available in rose gold or white gold (the Fancy models are set with 128 diamonds and have mother-of-pearl dials; the Classics have guilloché dials and the Gent models have plain dials). These are 36mm x 9.64mm cases, and I have to say the Gent model was quite charming for the few minutes I had one on my wrist during our Baselworld meeting with Moritz Grossmann; for a person with the right expression of personal style it would be a very characterful daily wear watch – it’s not what I’d wear for, I don’t know, mulching the back forty on a warm spring weekend, but I think it’d prove surprisingly versatile and we’ll try and spend more time with one hands-on, later this year.

Tefnut Twist Gent and Fancy

Above, the "Fancy" model in white gold, and the "Gent" model in rose gold.

The starting price is a bit on the steep side at at €29,900, but in this case, if you can afford it at all, I think you’re getting a lot of real originality for the money. This was a really charming, clever, well thought through introduction from Moritz Grossmann that’s launching in just enough variants to make it interesting to a pretty wide audience. The Tefnut Twist struck me as a rare but welcome example of an inventive technical solution, and novel aesthetics, working hand in hand.

The Tefnut Twist: movement, caliber 102.2, hand-wound, adjusted in 5 positions; 48 hour power reserve with twist-action winding; plates and bridges in untreated maillechort/German silver. Cases in white or rose gold; all offered on alligator straps with matching precious metal pin buckle. More info on the Tefnut Twist is right here at


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