ESA / ETA ‘Delirium’

While Ebauches SA (ESA), Omega, Girard-Perregaux, and others were trying to create the best and most precise high-end quartz movement, Seiko, Ricoh, Texas Instruments, Intel, Motorola, and others were simplifying and commoditising the technology. By the mid 1970s it was obvious that the Japanese were far ahead of the Swiss. Seiko and Citizen were producing excellent and reliable quartz movements and these were attracting customers away from the traditional Swiss brands. Seiko was introducing one or two movements per year by the middle of the decade, and prices had dropped to mass-market availability (4).

In 1978, just before the peak of the ‘quartz crisis’, American businessman Gerry Grinberg demanded Ebauches SA (ESA) to develop an ultra-thin movement before they lost the entire market to the Japanese. Grinberg had made a fortune building Piaget into a powerhouse for ultra-thin luxury, mechanical watches but watched that market evaporate as Seiko and Citizen pushed quartz thinner than any mechanical movement. He offered 2 million CHF, if ESA/ETA could deliver an ultra-thin 9 ligne quartz movement for use in a new line for his ‘Concord’ luxury watch brand for the USA (1,4).

Domestic Fight for the Thinnest Watch

The beginning of the ultra-thin quartz race was made by Seiko, who developed and delivered their cal.: 41 in 1974. It was 3.8 mm in height, which was much less than competing movements. In May 1978, Citizen introduced the ‘Exceed Gold’, an ultra-thin watch with a remarkable 0.98 mm thin movement. The production watch measured 4.1 mm thick, due to the height of the battery and hand set. Seiko was Citizen’s main rival, and they had long used the same strategy for their offerings, with high-end models cased in gold calling attention and widely available steel offerings drawing sales. Seiko was also emphasising the thin profile of their quartz offerings, steadily dropping millimeters throughout the decade. 

On 20.7.1978, just a few months after Citizen’s announcement, Seiko announced the slimmest watch in the world. Their new cal.: 9320 measured just 0.90 mm thick, narrowly edging aside the Citizen offering, but they paired it with an amazing 2.5 mm thin case, also selling it through Tiffany’s in the USA. This move by Seiko, entering the American luxury watch market, circumventing the well established distribution paths of Gerry Grinberg, motivated him to challenge Ebauches SA to develop an even thinner luxury watch (4).

The Swiss strike back

Lead by technical director André Beyner, ESA was best positioned to construct the ultra – thin quartz watch Grunberg had demanded (4).

The difficulties encountered in the conception of the watch included the fact, that the necessary components to build such a watch were too big to ensure the construction of an ultra-thin movement. The solution was to use the back plate as assembly platform and to insert the components from above, this would avoid to use space demanding bridges and additional movement plates. Thus, the main feature which allows for the ultra-thin construction is that the watch consists of only 3 construction levels, as compared to a conventional watch which has 7 construction levels (3).

Work proceeded at a furious pace for the 5 months needed to develop the watch (6).

Anton Bally. Picture credit (8)

The legendary movement designer Anton Bally developed a movement that spread the components horizontally to reduce thickness. It was Beyner himself who decided to integrate the movement and case into a single unit, latter developed by Maurice Grimm, who later will develop the ‘central tourbillon’ for Omega in 1994. All components were attached directly to the unitised body, with the dial, hands, and crystal completing the watch. In order to keep the slimness of the watch, the concept disposed of the crown. To adjust the time, a tiny button on the backside needs to be repeatedly pressed.

The Swiss conglomerates were reeling as quartz movements gained market share, and the now-legendary Ernst Thomke was in charge of production. He took charge of the ‘Delirium Tremens’ project (and soon all of Ebauches SA) and drove it to production (4).

The entire watch was produced by Ebauches SA, the caliber was named ‘ESA 999’. ETA assisted with the production and referred to the watch as cal.: 999.001. ESA and ETA will merge to ETA in 1985 under the umbrella of SMH. On 12.1.1979, at joint press conferences held around the world, Ebauches SA announced the ‘Delirium’. The then world’s thinnest watch measured just 1.98 mm thick and was sold by Concord, Eterna, and Longines under the names Concord ‘Delirium’, Eterna ‘Espada’, and Longines ‘Feuille d’Or’. IWC also offered this model as their ref.: 3000 IWC Quartz (1). About 11,000 watches were produced and sold. It was not a commercial success, considering the selling price of over 4,500 US$ at the time (2).

Further Iterations

Already in June / July 1979, Ebauches SA announced another Delirium (Delirium II) model that measured just 1.44 mm thick. Due to the ultra-thin design, it was intended only for collectors. ETA manufactured the entire watch, referring to it as cal.: 999.301 (1). ‘Delirium III’, a ladies version, was released in January 1980. ETA manufactured the entire watch as well, referring to it as cal.: 999.401 (1). The ‘Delirium IV’ was introduced in December 1980. At just 0.98 mm thick, it remains the thinnest watch ever produced. Rather than hands, these watch featured revolving sapphire discs engraved with a line. The sapphire crystal measures just 0.19 mm thick, and the special battery, produced by Renata is just 0.80 mm thick. Different ‘Delirium’ iterations continued to be developed until 1992 (1).

One further development which can be regarded as ‘following the trend’ of ultra-thin watches is the Omega ‘Dinosaure’ (cal.: 1355) issued in 1980, of which it is not clear if inspired or derived from the development of the ‘Delirium IV’ by Ebauches SA.

Project P-29

Prototype of the thinnest automatic tourbillon watch (2.7mm). Picture credit (9).

One very special derivate rising from the research for the slimmest quartz watch was the development of an ultra-slim automatic watch based on the construction principles of the ‘Delirium’. Developed also by André Beyner and Maurice Grimm as project P-29, the concept was patented the 24.10.1980. It was ultimately rejected by Ebauches SA and shelved. Both engineers later left Ebauches SA and used that concept of an ultra-thin automatic system to create an ultra-thin tourbillon watch. Only few prototypes were built of this first automatic ultra-thin tourbillon before looking for a manufacturer who would be interested in marketing such a watch. Audemars Piguet showed interest in the new concept and at the Basle fair 1986 their model ‘Ra’ was launched, of which about 350 pieces would be sold in the following two decades (9).

The Legacy: Swatch

In parallel to the differentiation of the ‘Delirium’ concept into different iterations, Ernst Thomke of ESA and Paul Renggli of ASUAG directed their teams to also leverage the ‘Delirium Tremens’ design into a more practical and less expensive watch. As Thomke said at the time (4):

The future is in innovative finished products, aggressive marketing, volume sales, and vertical integration in the industry.”

Jacques Müller (left) and Elmar Mock, the self declared ‘mothers’ of Swatch. Picture credit (7).

The ‘Delirium Vulgare’ (Delirium for the masses), as the concept was named, stalled until one fateful day of 1980: ESA engineer Elmar Mock’s friend Jacques Müller was an expert on inexpensive mechanical watches and he joined Mock in the study for the introduction of plastic elements for watches. They gathered seven patents, but Mock could not ensure a proper quality with the machine they used, so he wanted to apply for the purchase of a more modern but expensive Netstal plastic-injection machine (5).

Ernst Thomke. Picture credit (5)

The investment would be 500’000 CHF. As Ernst Thomke got the forms to approve the money, he wanted to have exact facts about the investment, so he scheduled a meeting with Mock on Thursday the 27th of March 1980 at 1pm. Mock got informed at 11am of the same day about the meeting, this left him about two hours to get his concept ready. He got back to Müller and together they came up with the idea of a plastic watch, where, as for the ‘Delirium’, the base of the case would carry the movements components. A Plexiglas crystal should then be hermetically welded on top of it (5).

Mock and Müller managed to grab a pink and a blue pens to draw some sketches, with which Mock then rushed to Thomke for the 1pm meeting. Thomke was already in a bad mood before the meeting, so when Mock presented him his idea, Thomke asked him if he was mad wanting to spend half a million Swiss Francs for a useless machine. Mock explained that they would be able to produce inexpensive plastic-watches with it and handed over the sketch he and Müller had made (5).

The sketch Elmar Mock presented to Ernst Thomke for the meeting the 27th March 1980. Picture credit (5)

Thomke took a glimpse of the sketch, realised the ingenuity of the idea, but said nothing. He confiscated the sketch with the comment, the idea would be completely wacky, as other engineers would already work on a similar project for two years with no results. Shortly after, Mock’s direct supervisor Urs Giger stepped into his office, telling him that Thomke wants Mock to be freed from all his responsibilities. He and Müller would get the new injection machine and would get six months to work on that Plastic-watch project up to building a prototype in all secrecy. That was a triumph for Mock and Müller. They moved to a hidden office at ESA and worked 18 hours per day for seven days a week. In December 1981 five prototypes were presented, which worked perfectly, after having solved all kinds of problems. Mock and Müller had created an amazing product with just 800’000 CHF of initial investment. Despite some changes, the basic concept remained the same until this day. Swatch was officially launched the 1.3.1983 (5).

Ebauches SA, Cal.: 999, ETA Cal.: 999.001, ‘Delirium I’ Prototype, 1978

Category: functional, aesthetic prototype, proof of concept (for Swatch)

Description: Rectangular 18k gold cased prototype. Back stamped with Swiss hallmarks for 18k gold. Rectangular, gold dial with central, circular depression to house the hands, ‘ETA Swiss Quartz’ logo in black at ’12’, ‘Delirium’ at ‘6’. Black coloured hour and minute hands, no second hand. Sapphire crystal (0.28mm thick).

Dimensions: 24.5mm, lug – lug: 29.6mm, 1.98mm thick, lug width: 18mm

Movement: ESA 999, ETA 999.001,

Additional info: This is one of just a few surviving prototypes for the first version of the ‘Delirium Tremens’ watch. It is identical to the one presented at the ‘Cité du Temps’ in Bienne (other than being marked with ‘ETA’ instead of ‘ESA’. It is not surprising that even a functional prototype is made in 18k gold, as the material is very soft and it is thus crucial to test for the deformability of the watch, during normal wear, prior to production. Moreover, the whole watch has been designed, developed and constructed within 5 months, this leaves not a lot of time for producing different functional prototypes.

The special and revolutionary feature of this watch is, that the main bridge of the movement is at the same time the biggest part of the case, so that the whole watch (as there is no separate movement) has been named ESA 999 or ETA 999.001.

This watch can be considered a proof of principle for the later development of Swatch.


  1. Watch Wiki
  2. Wikipedia
  3. Un Jour Une Heure, RTS Short Documentary, 22.1.1979, Bernard Guillaume-Gentil – French
  4. Grail Watch
  5. Swatch – Prototypes
  6. Le Temps
  8. Grenchner Tagblatt
  9. Revolutionwatch