With the World Time Chronograph ref. 5930, Patek Philippe presents a watch with two complications that are not usually found in the same watch: chronograph and world time. As is usual for Patek Philippe, the watch is like an iceberg: the easy-to-use simplicity of the interior hides a ferociously complex mechanism within.
Most so-called GMT watches show local time on hour and minute hands, and a second time zone with another hand or subdial. This piece operates according to a different concept: local time is shown on hour and minute hands, and the time in all other time zones is shown on a 24-hour ring. To set up the watch, you select the local time zone (London in the photo) and set the local time. So now you can read off the time in any other time zone, using the 24-hour ring. This is in two colours, silvery and dark blue, to make it more obvious that, for example, it’s just after 4 in the morning in Mexico City. When you travel to a new time zone, you use the pusher at 10 o’clock: with every push, the hour hand advances clockwise one hour, the city ring advances by one time zone, revolving anticlockwise, and the 24-hour ring advances correspondingly, also anticlockwise.
While you are changing the time zone using the pusher, the gear train and the minute hand continue unaffected, so that the watch retains its overall timekeeping precision.
It’s interesting to compare this watch to IWC’s Pilot’s Watch Timezoner Chronograph, another piece that combines the two functions in a fairly similar way.
So on the Patek 5930, everything moves on the dial, except for the central guilloché section and the silvery chronograph seconds ring between the city ring and the 24-hour ring. Chronograph readings are shown on this continuous scale with quarter-second divisions, corresponding to the 4-Hertz speed of the balance wheel so that maximum chronograph precision is 1/8th of a second. Chronograph minutes are shown on the subdial at 6 o’clock. So strictly speaking, the chronograph can be used for elapsed times of up to half an hour. It’s a flyback chronograph, so that when it is running, pressing the pusher at 4 o’clock instantaneously resets and restarts the chronograph.
There is no continuous seconds hand. However, if you like the idea of a continuous seconds hand, you can simply start the chronograph and leave it running. The chronograph’s vertical clutch construction means that using the watch in this way does not diminish power reserve or timekeeping accuracy.
The mechanical CH 28-520 HU movement is based on the existing CH 28-520 PS chronograph calibre with column wheel and vertical clutch, combined with the world time module. The two sections were optimized and slimmed down so that the complete movement is just 7.91 mm thick, enabling the watch itself to be no thicker than 12.86 mm. This compares favourably with the IWC Timezoner Chronograph which is 16.5 mm thick. The movement is visible through the sapphire caseback, with all the beauty you would expect from Patek Philippe: circular graining and a Calatrava cross on the rotor, bridges with circular graining and polished bevels, gold-filled engravings and so forth.
Case and dial
The watch is in a white gold case, 39.5 mm in diameter and 12.86 mm thick. The centre of the dial is decorated with manual guilloché, while the chronograph 30-minute counter has circular graining. Hour and minute hands have a SuperLuminova coating for visibility in low light conditions. The blue colour of the dial matches the navy blue alligator strap with Calatrava clasp in white gold.
Reference and price
The Patek Philippe World Time Chronograph, reference 5930, costs €67,987.