The Elusive IWC 5251

Part Three The Movement

Photo 6 – even in a bad photo, the beauty of the movement is apparent.

As Michael and Ken have declared, the raison de’ etre for this watch is its movement. Viewed through the sapphire exhibition back, it is striking both for its design as well as its appearance. During my discussions with Michael prior to purchase, he called this “one of the great movements in the history of watchmaking, as well as quite rare…” When a guy like Michael Friedberg has this to say about a watch movement, no further confirmation is required. Even a novice though, can look at this piece and assume, with great confidence, that it is special.

The history of this movement goes far back into the history of IWC, yet is, at first, somewhat confusing to follow. The catalog, in an effort to simplify things, actually ends up being misleading. The movement in this watch began life in 1927 as the Cal 95, changing to the 952 with the addition of shock protection, and is now 9521 – specially designated for the gilded adornment and moonphase complication particular to this model. All of these movements were 17”’ ligne, and remarkable for their less than 4mm thickness.

Photo 7 – the calibre number is engraved below the balance wheel.

The Cal 9521 remains a full-bridge design (2 bridges and 4 cocks, actually) and is comprised of 161 different components, including the hand-formed Breguet balance spring and 19 jewels, many of which are set in gold chantons. IWC characterizes this arrangement of parts as providing “such astonishing harmony and precision that it easily surpasses the standards set by the Swiss Chronometer Testing Institute“. Add to that bit of modest advertising the fact that the movement is gilded, and you have one of the most beautiful movements ever produced by this venerable Swiss watch company.

As for accuracy, I’ve not yet developed a great interest in timing watches down to their seconds-per-day variation. I collect watches more for their art than their accuracy, but in casual observation, the 5251 appears to fall well within the COSC tolerances. In fact, it is IWC’s objective to produce no watches that lose time, carefully regulating them to -0,+7. As the entire watch undergoes a 27-day test program and is adjusted in 5 positions, accuracy issues should be minimal. In my opinion, the issue with this watch is one of execution, not positional variations in timing. I did once try and verify the 18,000 bph, but had to stop at 2,437 because my vision became blurred.

Photo 8 – The classic construction is at all times visible through the transparent back.

Continue to Part Four