The principle of the natural escapement was devised by Abraham-Louis Breguet in the late 18th century. Its ability to provide two direct impulses per cycle as opposed to the single direct impulse of the detent escapement or the two indirect impulses of the Swiss lever is a key reason it is one of the most theoretically ideal escapements for a wristwatch. However, like all escapements, it has its drawbacks. This includes the ability to self-start only within a very narrow oscillation range, approximately ±4.5° from the centre line, due to its asymmetrical locking and impulse design. Moreover, integrating an escapement with two escape wheels into a tourbillon watch presents unique challenges.

This is because if both escape wheels are driven against a fixed fourth wheel, they will rotate in the same direction, which simply goes against the principles of a natural escapement. The first watchmaker to overcome this challenge was Derek Pratt. However, his escapement was based on the principles of Daniels’ independent double-wheel escapement in which the escape wheels moved alternately. His creation, the Double-Wheel Remontoir Tourbillon pocket watch, was completed in 1997 as an entry for the Prix Abraham-Louis Breguet. Despite its ingenuity, the watch ultimately lost to Carole Forestier-Kasapi’s entry, which would later become the groundbreaking Freak in 2001.

The Freak incorporated a silicon natural escapement and could be described as a tourbillon but only in the broadest sense, as its once-per-hour rotation is far too slow to counteract positional errors caused by gravity in the manner of a traditional tourbillon. The debut watch of Japanese watchmaker Takashi Aigaki, the Direct Impulse Tourbillon, is therefore the first wristwatch to pair a natural escapement with a tourbillon.

The Watchmaker

Born in Kumamoto, Japan, Aigaki initially aspired to become a professional BMX racer. However, a BMX accident landed him in the hospital where he chanced upon a documentary about Swiss watchmakers on TV. He enrolled into a watchmaking school in Tokyo and upon graduation, began his career at Richemont Japan in 2007, where he spent six years managing Piaget watch service and repairs. In 2013, he moved to Switzerland and joined Kari Voutilainen’s workshop, where he spent a decade honing his skills.

Aigaki began in the machining workshop, mastering techniques such as burnishing, pinion polishing, and tempering – skills he considers fundamental to crafting high-quality watches. With no formal trainers at the time, he researched and refined these techniques himself, building a strong practical foundation. After several years, he transitioned to the watchmakers’ workshop, where he assembled and adjusted complete movements. His most remarkable achievement was adjusting a movement for Besançon Observatory certification – a special commission for a unique timepiece with a natural escapement.

Last year, at the age of 40, Aigaki established his own company and set up a workshop in his Neuchâtel apartment. He has since completed the first prototype of the Direct Impulse Tourbillon. The majority of the watch was made using hand-operated tools and only three pieces will be made in total.

The Watch

The Direct Impulse Tourbillon is a classically proportioned watch. The case is 37mm, in stainless steel, with a press-fit case back. It is entirely polished and features a stepped bezel. At first glance, the dial is very unassuming but a plethora of traditional watchmaking crafts reveal themselves at close range.

Made of silver, the dial underwent a traditional finishing technique known as Breguet frosting, a form of depletion gilding. This method involves heating the silver to create a thin oxide layer on its surface, which is then carefully removed with an acid mixture. This cycle is repeated several times, progressively purifying the silver and enhancing its surface. The outcome is a pristine, silvery-white finish that resembles frost.

The dial markings, including the minute track, logo as well as a fine crosshair are all engraved by hand. The sub-dial is a separate inlay that was also made completely by hand and features a guilloché pattern created on a straight-line engine. It is set into a ring made of carbon steel which has a black-polished top surface. The hour markers, also crafted from carbon steel, are black-polished and faceted, with the quarter markers slightly elongated to align with the crosshair. The alpha-shaped hands are blued and each has its own central boss that has been black-polished on its upper surface.

The dial wears its craft so lightly that, without a keen eye for subtle displays of mastery, it could easily be overlooked. In contrast, the movement immediately grabs attention; it is exceedingly beautiful and is similarly executed in a “light-handed” way in that the going train is hidden beneath the dial, creating the illusion that the barrel and tourbillon are mysteriously disconnected. Both the base plate and bridges are made of German silver that has been rose-gold plated and given a frosted finish. The steelwork is finished to an extremely high standard. The winding wheels have polished teeth and are secured to the bridge with polished screws. The large ratchet wheel has two integrated clicks that are bevelled and polished. They are fixed to the inner ring of the wheel which interact with a fixed ratchet hub with a large polished gold chaton.

Transplanting the gear train to the dial side along with having a tourbillon that’s hidden naturally results in a slightly thicker watch. It measures 12.5mm high but this deliberate choice pays off spectacularly, enabling the tourbillon cage to be as large as possible while lending an unusual airiness and depth to the movement.

Prominently displayed at six o’clock, the one-minute tourbillon measures 15mm wide. The cage construction is equally minimalist to reduce inertia. It is secured under a slender steel bridge that has been finely finished with internal angles. The balance is free-sprung with gold inertia screws and beats at a traditional 18,000 vph.

The Direct Impulse Escapement

At the heart of the watch lies the Direct Impulse escapement, which is based on the principles of a natural escapement.

It’s interesting to note that Derek Pratt was looking for a solution to incorporate George Daniels’ independent double wheel escapement in a tourbillon while Aigaki was seeking to use a natural escapement. Aigaki’s goal was to eliminate the two driving wheels typically found beneath the natural escapement as they introduced more inertia. Breguet himself fitted the natural escapement in his early tourbillon watches but they had driving wheels and the escape wheels were of different sizes – one with 12 teeth and the other with just 3 teeth.

The challenge in Derek’s case was that an independent double-wheel escapement requires each escape wheel to be driven by its own gear train, but a tourbillon, by design, cannot be driven by two gear trains as two gears can’t drive a single cage pinion.

As such, both Aigaki and Derek arrived at the same solution, which is to use a single gear train and drive the first escape wheel against a fixed fourth wheel while the second escape wheel is driven against a fixed wheel with internal teeth. This arrangement ensures the escape wheels rotate in opposite directions. However, Derek faced a greater challenge as an independent double wheel escapement requires that the escape wheels move alternately. He solved this with a pivotable assembly of the escape wheel-pinion unit and the use of remontoirs.

In a natural escapement, both wheels rotate in opposite directions but together. The teeth of the escape wheels are offset by half a step during adjustment so that they will alternately intersect the path of the impulse pallets and be alternately locked by the lever.

Notably, the escape wheels in the Direct Impulse escapement are mounted on either side of the cage. Typically, both escape wheels in a natural escapement are located next to each other as they have to be locked and unlocked by a central lever. Aigaki designed the lever for a small lift angle. It can’t be seen as it is much shorter, meaning it has less inertia. At present, images of the escapement are unavailable due to an ongoing patent application.

The Aigaki Direct Impulse Tourbillon is certainly an impressive watch on many levels and a breath of fresh air. It is technically accomplished and distinctive, showcases a mastery of craft and is executed with such tasteful restraint and elegance that’s in contrast to many other luxury watches today which are designed primarily as canvases for ostentatious displays of finishing. It shows that when the fundamentals of watchmaking, the excellence of materials, and the mastery of artisanal skill are properly grasped and applied, the harmony between aesthetics and mechanics emerges naturally, unforced, authentic and in this case, sublime.

Tech Specs

Movement: Manual winding; 40-hour power reserve; 2.5 Hz (18,000 vph)
Functions: Hours, minutes and seconds
Case: 37mm x 12.5mm; Stainless steel
Strap: Black leather
Price: Upon request
Availability: Limited to 3 pieces