Patek Philippe introduced its first Annual Calendar, reference 5035, in 1996. This model features functions for the day, date, and month, allowing it to differentiate between months with 30 and 31 days. As a result, it requires manual adjustment only once a year, at the end of February. The innovative reference 5035 was followed by the reference 5146 Annual Calendar in 2005. The key enhancements between the two models include an increase in size from 37mm to 39mm, along with the addition of a moon phase complication and a power reserve indicator, which adds visual interest to the dial. This particular piece is the reference 5146J, with the 'J' indicating “jaune” (yellow) to signify the 18k yellow gold case. It features a stunning concave polished bezel, four correctors for the calendar positioned on the side of the case, and a sapphire exhibition case back that reveals the beautifully finished automatic movement, caliber 324 S IRM QA LU, equipped with a 21k yellow gold rotor. The gray sunburst dial is adorned with applied 18k yellow gold hour markers and Arabic numerals at the 3, 6, and 9 o'clock positions. It includes two subdials for the calendar in English, a date display at 6 o’clock, a moon phase indicator, and a power reserve indicator. The watch is complemented by a slightly worn Patek Philippe leather strap with an 18k yellow gold folding clasp. Also included in the sale are the original inner and outer boxes! We love this combination of the gray dial, moon phase, and perpetual calendar. If you share our enthusiasm, get in touch!