F.P. Journe: The Quantième Perpétuel makes a complex calendar read simply

F.P. Journe’s Quantième Perpétuel places day and month windows together near the top of the dial and a large date below the central hands. Its calendar information is read through apertures rather than a cluster of pointer subdials. A reserve indicator occupies the left side, maintaining the manufacture’s taste for asymmetry.

The automatic calibre 1300.3 incorporates an instantaneous calendar change and accounts for month lengths and leap years. Like conventional perpetual calendars, it requires correction for the Gregorian exception in 2100. Platinum and 18K 6N gold cases are listed in 40 or 42mm sizes, with a height of 10.85mm. Both metals are illustrated.