Reference 5001

by Jack Forster

© February 2005 Jack Forster and

all images are clickable to enlarge unless noted




With the Portuguese Automatic the splendid hand-made 5000 automatic movement - to date the largest one of its kind on the world market - has been adapted for more delicate wrists and at the same time shed some weight. Whilst retaining the classical appearance of the legendary original Portuguese first made in the 1930s, with its appliquéd Arabic numerals, railway-style minute chapter ring and slim, swallow-style hands, IWC's designers have equipped it with all the features you would expect to find united in a high-performance mechanical wristwatch: the patented Pellaton winding system and the exclusive mechanism with its eminently legible date display. Together with other new and more advanced features such as the convex, coated sapphire glass, the two-piece case or the new back with its screw thread and sapphire glass, the Portuguese Automatic is the watch that would be developed in Schaffhausen if those two Portuguese businessmen dropped in today with a request for an unusually large and precise wristwatch.

two IWC Portuguese
left: 1993 reference 5441
right: vintage reference 325, ca. 1943

IWC caliber 97 (lepine variant of C98)
37.8 x 4mm


The watch: reference 5001 Portuguese Automatic

The IWC Ref. 5001 is a watch that at first glance could not be more straightforward in design and execution: a 'pocket watch for the wrist' in the great tradition of the Portuguese line, it's a very large, heavy, 'statement' watch with bold simple lines and a caseback affording a view of what is now, and for the foreseeable future, the largest automatic caliber in the world. And yet, under prolonged exposure, certain aspects of the watch begin to move to the foreground- qualities which, as we shall see, raise interesting questions about not only the Ref. 5001 itself, but about the direction in which modern wristwatch aesthetics and engineering are progressing in general.

The IWC Portuguese Automatic Ref. 5001 is the latest entry from IWC in the Portuguese series of wristwatches, which now features a full range of complications, including a chronograph, rattrapante chronograph, minute repeater, tourbillon, and a striking and dramatic perpetual calendar.

IWC reference 5000, introduced in 2000
(1.000 pieces in steel, 750 in rosé gold, 250 in Platinum)

 The Ref. 5001 contains the automatic IWC Cal. 50010, which is the most recent iteration of the original cal. 5000, introduced to the Portuguese line in 2000 as a limited edition, and then used in the Big Pilot's Watch Ref. 5002, a watch which has become something of a touchstone for IWC's subsequent philosophy in design. The Big Pilot's Watch is not so much iconic for later designs in a strictly literal sense, but it represents a strong commitment to both history, and to the notion of 'doing things big'- of making watches that both embody and to some degree transcend the prioritizing of functionality that has, for some time now, been IWC's stock in trade. These two poles of expression are both spectacularly on display in the limited edition version of the Ref. 5001, which consists of 500 examples in a solid-very solid- platinum case.

Indeed, the sheer size of the watch is the first thing one notices, for the IWC Portuguese Automatic Limited Edition looms large, both to the eye and on the wrist. This is not a watch that hides its light under a bushel- at 13.9 mm in height and 42.3 mm in diameter not only won't it fit under a shirtsleeve, it probably won't even fit under a jacket sleeve. Clearly, however, the Ref. 5001 is not intended to peek discreetly out from under a cuff- it's impossible to ignore for both observer and wearer, and at 138 grammes in platinum, a constant reminder of not only the weight of IWC's horological history, but of weight, period.

The case itself (and indeed, as we shall see the entire watch) is a mixture of overwhelming substance with strangely delicate, almost ethereal execution. The bezel has a mirror finished, carefully radiused concave flank, with a sharp edge transitioning to a flat mirror finished top. The body of the case is finished with a vertical brushing, and while the mirror finishing of the bezel gives a beautiful effect in combination with the long graceful hands, it may tend to pick up scratches rather quickly in every day use- the more so due to the sharp angle between the curve and flat top and the height of the watch itself.

The silvered dial is extraordinarily beautiful, without sacrificing any of the functionality that is IWC's trademark, and the pragmatic, slightly technical, yet elegant execution is rounded out with meticulously done applied numerals and bar markers at the hours, with a railroad minute chapter. The long leaf hands are beautifully formed and the large diameter of the dial really gives them room to stretch out; the two subdials for the small seconds and the power reserve articulate the surface of the dial without overwhelming it. 

One of the most wonderful aspects of this watch is the attention to detail of the dial; the hands for both the power reserve and small seconds are carefully finished, with curved surfaces that, like the larger hour and minute hands, scatter the incident light and provide much better legibility against the white dial than could be afforded by flat hands. Under virtually all lighting conditions the time is instantly readable- contrasting blued steel hands such as those offered on the steel version would marginally enhance utility as well as help relieve, at least to some degree, the starkness of the dial which is its only drawback, but taken on their own, the beauty of the platinum hands is inarguably appealing. Sticklers for maximum legibility might complain of the absence of luminous material, but it seems quite clear that such an addition would violate the intended aesthetics of the dial to quite an objectionable degree. 

The dial, in fact, is aesthetically faithful to the original Portuguese watch, almost to the letter, and at least based on the dial the ref. 5001 would be instantly recognizable to Rodriguez and Teixeira, the two Portuguese gentlemen who commissioned the original, were they to walk into IWC's atelier tomorrow looking for additions to their collection.

However, the dial is also, the longer one examines it, a bit disquieting. The taper of the hands is almost feminine in quality, and it is here that the watch actually begins, for me, to exhibit a certain conflict of design cues- the delicacy of the dial seems very much at odds with the severe lines and sheer physical bulk of the case. There's a broad shouldered machismo to the case dimensions that seems oddly discordant with the reserved formality of the dial; as if one had decorated a tank-turret with a tea-cosy.



The movement: IWC caliber 50010 Automatic Movement


IWC caliber 50010

Through the sapphire caseback- a gleaming thick affair with the slightly intimidating presence of a bank teller's bulletproof glass window- one can view the cal. 50010. The cal. 50010 is not merely a watch movement but also a piece of kinetic sculpture, designed to exhibit the action of the Pellaton winding system, famously described by eminent British horological writer Donald de Carle as 'a simple and ingenious system, well constructed and beautifully finished.'

Unlike earlier IWC movements using the Pellaton winding system, such as the famous cal. 8541 which found a home in, among others, the Ingenieur series of wristwatches, the cal. 50010 uses a rotor with two large cut-outs, allowing a more unobstructed view of the mechanism. The Pellaton winding system is one of my favorite designs; the sheer elegance of its conception and execution exert an undeniable charm not to be found in many other automatic calibers using conventional reverser wheel arrangements. The massive rotor turns a heart cam that operates two pawl levers via separate ruby rollers, which alternately idle on or gear to an intermediate wheel with angled, straight cut teeth that then winds the mainspring barrel via reduction gearing. Not only is the system a spectacularly elegant mechanical solution to the problem of bidirectional winding, which is in my opinion unparalleled for sheer creativity, it also avoids the use of the often small, complex, and trouble-prone reverser wheels that can be the Achilles' heel of other automatic systems.

crystal back and rotor

The massiveness of the rotor is potentially problematic as it is carried on a small diameter steel pin riding in a jewel set in the rotor itself; the issue of side load during a sudden impact, however, is somewhat mitigated through the expedient of mounting the entire rotor mechanism on its own shock spring, one of the few instances of a shock protected winding rotor of which I am aware in either a vintage or modern movement. The use of such a small central bearing, albeit a jeweled one, for such a large rotor may prove to be an issue over the very long term as the side-load of the rotor mass is distributed over a very small surface, however the extent to which this may present an issue in actual daily use is less clear.

rotor mounting

rotor bearing, back view


IWC Pellaton winding
IWC publication, 1950´s

Not coincidentally, the action of the Pellaton winding system is very beautiful to watch, and owners of the IWC Portuguese Automatic may very well find themselves spending more time with the watch off the wrist than on, the better to admire it. Overall the rest of the movement exhibits the careful, largely functionally oriented finish for which IWC is known, with a resolute refusal to indulge in the pyrotechnic visual effects for which other manufacture movements strive. The result is a mechanism that revels in its machineness, in the sheer kinesthetic appeal of mechanics itself. In such a movement, beauty is to be found not in the prima donna articulation of every visual surface, but in the visible integrity of function expressed in the most appropriate form.

IWC Pellaton winding, caliber 50010

The escapement of the cal. 50010 is, according to IWC, "identical" to that found in the famous IWC manual wind movement cal. 89; there is a two armed, screwed, uncut monometallic balance wheel featuring, in addition to the rim screws, two flat, eccentric meantime screws mounted on either arm; the latter allow for very fine adjustment of rate. There is also a conventional regulator index with micrometric regulator mounted above the overcoil hairspring, as well as an adjustable stud carrier. The stud carrier, like the index, is moved by an eccentric screw, which allows for very fine adjustment of beat; a very nice and noteworthy technical refinement. Theoretically speaking, the use of a completely freesprung balance, in which there is no index at all and final adjustment of rate is done by adjustment of the meantime screws, offers the possibility of greater stability of rate over the long term. However, one cannot fault IWC for using both the index and meantime screws together. Historically, this combination was used in many extremely high grade watches, and offers the potential for extremely fine adjustments to isochronism. Either option in conjunction with an overcoil hairspring can offer exceedingly refined performance and ultimately the issue is decided by the degree of care to which the individual watch is adjusted, rather than by the presence or absence of an index per se. IWC has an excellent reputation for taking care in the adjustment of its watches, which routinely exceed COSC standards, so the owner of a Portuguese Ref. 5001 may be confident that the watch will fulfill in performance the standards promised by its history and design.

a nice detail: IWC caliber 50010 case clamp:
A well tested and elaborate construction, proven in vintage counterparts; it allows the clamp 
to slide without need to remove both screws, which prevents from parts getting lost.

IWC´s earlier movements like C89, as well as the older pocket movements C74 and C98, were equipped with moveable hairspring stud carriers. The early automatic movements like C85 and IWC´s first ultra-thin movement C401 relied on a fixed hairspring stud and a swan neck fine regulator. The use of eccentric screws is not unknown; with the increasing use of thin movements, utilizing a flat hairspring with eccentric regulator screws became common practice. Thus the C50010 combines the best of both.

clockwise from upper left:
1 vintage IWC caliber 89
2 IWC caliber 50010
3 vintage IWC caliber 402
4 vintage IWC caliber 401
5 vintage IWC caliber 89 (side view)

Visually, the balance is on its own satisfyingly large, however it is somewhat overwhelmed by the size of the movement overall. It is, however, nicely echoed by the gold medallion, carrying the IWC logo, which forms part of the winding rotor.

IWC caliber 50010, dial side

On the dial side, the movement offers finish consistent with the visible portion; there is a non-instantaneous date change mechanism in which the hour wheel, through an intermediate gear, turns a date wheel with a spring-loaded arm that once a day engages the teeth on the inner rim of the date ring. This spring loaded arm is gradually compressed by the date ring, which is fixed in place by a jumper under pressure from a spring. The arm eventually stores enough energy to defeat the jumper and the date ring moves forward one increment, freeing the spring loaded arm on the date wheel from its engagement with the date ring and allowing the nose of the jumper to re-engage. This straightforward and reliable mechanism is made even more attractive by the beautifully formed steel jumper spring, where many movements use a simple and cheaper wire spring. It's very reminiscent of the style of springs used in many vintage pocket watch movements, and it is always delightful to see such unnecessary exercise of traditional craft, especially in a part of the movement usually visible only to the watchmaker.

IWC power reserve - planetary gear drive

One final feature worthy of note: the mainspring of the cal. 50010 carries a theoretical power reserve of eight days, but the watch will run for only seven days on a full wind. At the end of the seven day period, a stop mechanism engages the balance. This is intended to ensure isochronism for the entire operating period; modern mainsprings deliver fairly consistent power over most of their power curve but the last part of the power reserve often produces a significantly lower balance amplitude, to some degree, and in giving a watch with a functional seven day reserve an actual eight day reserve, this problem is minimized. The alert owner may thus manually wind the watch to store power if he or she wishes to do so as the end of the reserve is approached, whilst at the same time resting assured that the mainspring is delivering power consistently across the entire functional operating curve. 

The extremely long, powerful Nivaflex-1 mainspring is housed within a barrel made of anodized aluminum, in which a thin surface layer of aluminum oxide provides internal lubrication. An interesting historical note is that it is theoretically possible to use the same arrangement of planetary gears which activate the stop mechanism to also lock the rotor when the mainspring is fully wound. Historically this was a feature of other automatic winding movements, including the Felsa cal. 1565 "Inversator" and the Jaeger LeCoultre "Futurematic" cal. 497. In the vintage IWC calibers 74 and 98 (cal. 74 was the first used in a Portuguese watch), winding was stopped by a Maltese cross stopworks, the purpose of which is to prevent the mainspring from being wound through its final turn. This prevents excess friction between the coils from causing anisochronism during the first part of the power reserve. While a Maltese cross stopworks is probably not practical on an automatic movement, the use of a locking rotor would have been both a technically and historically interesting additional refinement that would have increased the sense of functional continuity between the cal. 50010 and the manually wound pocket watch movements used in the original Portuguese watches.

I am as divided in my own personal reactions to the IWC ref. 5001 as I have ever been about a wristwatch. I feel a very strong attraction in principle to the notion of a 'pocket watch for the wrist' and yet, that is not, really, what the ref. 5001 is. The original Portuguese watches were based on the IWC cal. 98, a relatively flat savonette caliber which allowed for a thin although very wide (42mm) watch, and the noticeable thickness and weight of the platinum limited edition ref. 5001 make it a much more difficult watch to wear than a thinner watch would be. There is, at least for me, considerable proprioceptive discomfort associated with actually having this watch on the wrist; the mass constantly pulls at the center of gravity of the forearm producing a subtle but persistent and ultimately disturbing sensation. This is, I suspect, partly due to the weight of the watch but even more due to its height, which displaces the center of gravity of the arm to which it's strapped just enough to be persistently noticeable.

IWC caliber 50010, rotor removed

To some degree this issue might be minimized by the use of a thicker strap. The black crocodile strap and platinum, single-fold deployant provided with the watch exude quality but the strap is perhaps too thin for such a robust and heavy case. While the strap is quite formal, the dimensions of the watch seem to call for a padded strap more along the lines of that used on the Big Pilot's watch- though such a strap might undermine the undoubted elegance of the Portuguese it might also go a long way towards obviating the nagging feeling that the massive case calls for a strap to match. However, it's hard to take issue with the impressive visual impact of the strap and watch taken together.

One can't really object to the notion of an automatic pocket watch per se- no less a luminary than Breguet (among others) made self-winding pocketwatches, so there is a precedent- but in terms of finding a rationale for size and height in its actual design lineage I personally find it hard to ignore the feeling that to some degree, this is a watch which is big merely for the sake of being big. The idiom of pocket watch design is slightly undermined, I feel, by the use of a caliber which derives so much of its basic engineering from movements designed for wristwatches. The combination of the two is to me somewhat unsatisfying and I found myself wishing, despite the impressive qualities of the movement in the ref. 5001 taken on its own, that the Portuguese series were based on the savonette pocket watch movements that IWC still has in production. I feel I should admit that the exaggerated size of the cal. 50010 is for some reason much less bothersome to me in the context of the Big Pilot's Watch, which seems sufficiently clear in its historical antecedents to plausibly support the use of an oversized automatic caliber, but the ref. 5001, at least to my taste, is not as successful at reconciling the lineage of the original, manually wound Portuguese watches with their modern descendant. As a result, despite the many laudable individual components,I found the ref. 5001 taken as a whole to exhibit a certain sterility- the gorgeous dial and the wonderful movement existing in splendid isolation from each other, as if the height of the watch were an unbridgeable distance in not only physical but aesthetic space as well.

On the contra side of the argument, it is worth noting that in the development of caliber 5000 and 50010, IWC appears to have deliberately set out to advance and expand the design idiom of the Portuguese watches, rather than simply repeat the execution of the historical cal. 74 and 98 watches, no matter how timelessly elegant these may have been. The incorporation of the Pellaton winding system into a 17 ligne "pocket watch for the wrist" represents a clear attempt to link, in a single design, two distinguished but heretofore distinct elements in the history of IWC: a manually wound pocket chronometer cased as a wristwatch, which alludes not only to the marine chronometer tradition but also to the famous IWC B-Uhr and its descendant, the Big Pilot's Watch, with the separate history of elegant automatic wristwatches represented by the cal. 8541. In a very real sense this is a sophisticated integration of aesthetic and engineering which will offer real appeal to the serious IWC enthusiast with a knowledge of the company's history. The risk, of course, is that the referencing of so many design cues may produce incoherence rather than depth, and it's by no means an easy feat to execute.

However, these personal reservations will not, I expect, diminish the joy that IWC enthusiasts feel in the new presentation of the Portuguese line. My own few personal reservations aside, as large wristwatches go there's no doubt that objectively the ref. 5001 offers much; a dial with few rivals in elegant and meticulous execution and a movement which is absolutely unique in modern production- the largest automatic movement in the world, which, however it may or may not respect practicality in terms of sheer size, offers an experience of a kind of horological kinetic sculpture that would be difficult to find anywhere else. And of course, it has always been to IWC's considerable credit that in their largest watches, they use a movement that is actually an appropriate size for the case!

At the beginning I commented that the ref. 5001 raises interesting questions about the direction modern wristwatch design and aesthetics are headed, and in some ways, I feel that the gradual disconnect between practical necessity and actual execution that has occurred in mechanical watches, perhaps driven by the unquestioned superiority of quartz timekeepers, has repositioned mechanical watches in a way that fetishizes mechanical integrity- that is to say, isolates it as an aspect of the experience and threatens to make it simply another display aspect of the watch. Whether or not any manufacture really succeeds in truly respecting pragmatic mechanical integrity, and, more importantly, whether it can do so in the context of useful innovation, is an interesting critical perspective from which to examine not only the ref. 5001 but any modern luxury watch, where the display and visual aspects enormously inform design. The IWC ref. 5001 is, to my way of thinking, not only intended to embody values such as historicity and mechanical integrity, but also to display them, to broadcast the wearer's endorsement of those values. The risk is always, of course, that the display may actually undermine the very values it seeks to signal. How well the ref. 5001 balances these two sometimes conflicting priorities must be left to the taste of the individual, but at the very least, one can say that the Portuguese Limited Edition wouldn't even raise the question if it didn't have a very strong, and in many ways very impressive, character of its own.

I am indebted to Michael Friedberg, the moderator of the Official IWC Forum, for his many valuable articles on the history of IWC and especially the Portuguese line. I am also grateful to technical staff for their corrections and input. All opinions expressed are of course, mine alone, as are any errors.


Jack Forster


data sheet

caliber 50010

  • Diameter: 37.8 mm
  • Height: 7.2 mm
  • Jewels: 44
  • Frequency: 18,000 A/h
  • Power reserve: 7 days, minimum 168 hours
  • Functions:
    • Center hour and minute
    • Small second at 9 o'clock with stop second
    • Date window at 6:00 o'clock with instant date change
    • power reserve at 3:00 o'clock
  • Pellaton bi-directional winding system
  • Breguet overcoil
  • 18kt rotor medallion
  • Nivarox mono-metallic balance
  • Rotor with circular Côtes de Genève decoration
  • 3 positions pushrod
  • Fine index adjuster with dual excenter screws
  • Incabloc shock protection
  • Shock protected rotor bearing

data sheet

Reference 5001

  • Movement: IWC manufacture cal. 50010
  • Limited edition of 500 pieces in Platinum
  • Power reserve, date, small seconds
  • Crystals: sapphire, front and back
  • Water resistance: 3 bar 30 meter
  • Dimensions: 42.3 mm x 13.9 mm
  • Platinum: 138 grammes
  • Rose gold: 115 grammes
  • Stainless steel: 95 grammes


addendum: pictures fixed


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This article first appeared in International Watch Magazine.

Copyright February 2005 - - all rights reserved