Superb quality under the radar excellence. This perfect complication with a lot of functions in a relatively slim case. Watch is from 2015 and serviced by Patek in 2021. Full set with all the papers, booklets boxes and service papers. The day, month and moonphase subdials are perfectly proportioned on the dial and symmetrically triangulated with respect to each other. The white gold stick hour markers along with the 3,9, and 12 hour markers complement the white gold case but not enough to be overwhelming. The date window at 6 o’clock is the only number one really needs to read and it only has to be adjusted every end of February. The official definition of the 5146 mechanism is Caliber 324 S IRM QA LU. S delineates centre seconds sweep. IRM is French for Indication Réserve de Marche, meaning power reserve located at twelve o’clock. QA meaning quantième annuel which is an annual calendar. The date need only be changed annually at the end of February provided the watch is wound perpetually. LU represents lune in French for the moonphase. Again it baffles me, 4 complications in a reservedly thin 5.32 mm mechanism within a 11.23 thin case. That I guess is haute horlogerie.