Klaus created the DaVinci perpetual calendar in 1985. The DaVinci's coordinated perpetual calendar plate then was considered revolutionary. For the first 5 years of Lange's reincarnation, he spent a week each month in Glashuette, assisting in the development of their movements. For the past 4 1/2 years, Klaus headed the design team for IWC's brand new in-house movement, the Calibre 5000.

To understand Kurt Klaus, one needs to understand his inventions. To learn more about Klaus' invention of the perpetual calendar for the DaVinci, click here. This construction for the first time allowed all calendar functions to be set at once by the crown --that is, setting the current date sets the month, year and moon phase as well. Some 15 years later, Klaus has done it again with IWC's totally new, in-house movement, the Calibre 5000, which generally is described in a prior article (click here). While using the best of tradition, the Calibre 5000 contains many innovations -- it is among the first automatic movements with lengthy autonomy and the only one that stops the balance towards the end to avoid isochronism error.

I had the pleasure of recently spending time with Herr Klaus and being taught by him (at least as much as this amateur student can absorb) about how the Calibre 5000 works. More importantly, it taught me a great deal about his philosophy of watchmaking and, in a sense, IWC's philosophy.

In fact, Klaus began our discussions by telling me that the Calibre 5000 makes a statement -- he said that it is "not just a construction" and instead the movement reflects a "philosophy" of watchmaking. There is a theme behind each of the decisions that was made when developing the movement. To Klaus, the Calibre 5000 combines new technology with old techniques.

That is not surprising, considering that Kurt Klaus has been at IWC for 43 years. He, more than anyone else, must carry on the tradition. Albert Pellaton, perhaps IWC's greatest technical director, was Kurt Klaus' master teacher. Pellaton taught Klaus that innovation is inherent in that tradition, but there must be a respect for classic principles at the same time.

The Calibre 5000 embodies these premises, even down to its screws. Many companies use heat-treated, blued screws as a mark of quality. Klaus vetoed them in IWC's new movement. To him, a screw-head can be blued inexpensively, but a polished screw-head takes more time and is more beautiful. More importantly, the great IWC pocket watch movements --the Calibres 95, 97 and 98, all starting in the 1930s-- never had blued-screws. These were nickel-plated calibres with white screws. The Calibre 5000, a pocketwatch size movement, would embody that same tradition.

Yet Kurt Klaus believes that a tradition of innovation itself requires innovation. He believes that the Calibre 5000 is the first series-produced automatic 7-day movement. That entailed several requirements and further developments.

A 7-day automatic or self-winding movement requires more space. The mainspring is longer and the barrel is bigger. To wind the watch quickly, a larger oscillating weight (that is, rotor) is required. Unlike other companies that have 7-day manual wind movements, which usually require lengthy winding, an automatic movement after a start can wind itself. The end result of this would be perhaps the world's largest automatic watch movement.

The need to produce a large movement in turn resulted in further consequences. To Klaus, a "big movement needs a big balance". The primary reason for this is aesthetics. In comparison,  he told me that the Lange One, which is a relatively large movement, has a smaller balance due to the number of complications, especially the oversized date.

IWC's new large, slow beat movement in turn would use a Breguet overcoil. In fact, Klaus said that a small balance, high-beat movement in a wristwatch does not need a Breguet overcoil --its accuracy over time, in actual use, would be about the same regardless. But a large movement is a different story; according to Klaus, the overcoil becomes increasingly important. The only problem is that, in Klaus' opinion, a Breguet overcoil should not be made by machine and must be made by hand. Every hairspring requires a different bend and there is no empirical way to judge that. It is a difficult skill to learn; IWC currently employs three "regleuse". Their skill requires experience, as well as a dexterity and patience best suited, in Klaus' opinion, for women. "You need good fingers", Klaus told me and added that a good regleuse can command the same salary as the best watchmaker.

At that point in our discussions, I had learned that the goal of a 7-day automatic resulted in the following primary design decisions:

• a large movement

• an efficient winding system

• a large balance

• a Breguet overcoil

Of course, each of these decisions prompted still further decisions. The winding system adopted Pellaton's ingenious Cal. 85 invention, with its heart-shaped cam. This simple and ingenious system has been praised for its efficiency and reliability. Instead of having a series of gears connect the rotor to the barrel wheel, a cam oscillates between two rollers (depicted at right in red). This energy is transported to two clicks (depicted in yellow) which ratchet against the barrel teeth, winding the the mainspring inside the barrel.

Albert Pellaton had developed a barrel for IWC's Calibre 853 in the late 1950s using aluminum oxide, an aluminum alloy treated with electric oxidation and which had the same hardness as a ruby. It had worked flawlessly, with easy glide of the mainspring and virtually no wear (in contrast, earlier Cal. 852 barrels are routinely replaced with Cal. 853 barrels during servicing). IWC's new Calibre 5000 would have an aluminum oxide barrel. But that, in turn, required a separate barrel head. It was very difficult to mill teeth in aluminum oxide, so brass was used and screwed on the top of the barrel.

While the winding system and the barrel were based on IWC's Cal. 85 designs, as originally developed by Albert Pellaton during the late 1940s through the 1950s, the escapement of the new movement would be based on IWC's Calibre 89. This ultra-reliable manual movement was introduced by IWC shortly after World War II and continued for more than 40 years. Klaus wanted to use what he considered the "best of IWC". IWC's famous Mark XI watch used the Calibre 89 and the military issue Mark XI's were all chronometers. According to Klaus, if was good enough for pilot watches, it was good enough for the new Calibre 5000.

The Calibre 5000 therefore adopted the pocketwatch principle of a larger escapement and correspondingly larger balance. However, because Klaus considered the Cal. 89 escapement as difficult to regulate, he took the regulator design from the Cal. 8541. The regulation still does not appear simple. The screwed balance was used partially for appearance, but it allows first adjustments (such as if the watch initially is one minute fast) and positional adjustment. Eccentric pins, not screws, on the regulator are primarily used to adjust beat. The spring must be perfectly centered.

Unlike most other movements, the Calibre 5000 has a power reserve with a mechanism to stop the balance, as the spring becomes close to fully unwound. The amount of winding goes through a gear train and as the indicator approaches 7 days of unwind it triggers a pin on a wheel. A "differential stop spring" then serves as a brake on the balance. When I asked whether any other watch incorporated such a clever design, Herr Klaus said only one: "the Lange Pour le Merit, but that differential stop spring stops the cage of the tourbillon". When I asked whether stopping the balance could be bad for a watch, as some other companies contend, he just shook his head, "I've never seen danger in 50 years" and pointed out the reliability of IWC's Calibre 89.

Kurt Klaus considers the Calibre 5000 as having the best of all worlds: a combination of new technology but using old techniques. He did not want to make something new just to make something new, and he wanted the movement to have practical utility. When the first prototype was made, he wound it slightly, enough to get the watch started without the tedious stem winding of most 7-day manual wind watches, and then wore the watch over a weekend. When the work-week started, he left the watch in a drawer. The next weekend, he took the watch out --its timekeeping was still perfect and he wore it again.

He views this as practical and innovative, but based on IWC's tradition. While he says that Lange makes a very beautiful watch, he wanted to make a technical watch. In IWC's tradition, he has produced an "Engineer's watch". But in all modesty, he says that the Calibre 5000 "is not my movement --it is from a group".

Kurt Klaus does admit that he created the DaVinci perpetual calendar and, back in the quartz ages of 1985, "it changed the culture". He hopes the Calibre 5000 will do "a little bit of the same". And he hopes that, like the Calibre 85 and its progeny, this new movement will last 35 or 40 years.

Albert Pellaton would have been proud of his pupil.