Patek Philippe

Patek Philippe

Reference 961

A yellow gold minute repeating instantaneous perpetual calendar openface keyless chronometer watch with moon phases, 24 hour, leap year indication and Earnshaw-type spring detent escapement, Made in 1990

Dial: silvered, Roman numerals, blued steel spade hands, four satin-finished silvered subsidiary dials indicating date with constant seconds, day in French combined with 24 hour indication, month in French combined with leap year indication, moon phases

Calibre: cal. 21''' RMDQ damascened nickel movement with Earnshaw-type spring detent escapement, 29 jewels, bi-metallic compensation balance, wolf's tooth winding, minute repeating on two steel gongs

Movement number: 866'797

Case: 18k yellow gold, hinged back to reveal transparent crystal dust cover

Case number: 2'837'630

Size: 58 mm diameter

Signed: case, dial and movement

Accessories: Patek Philippe Extract from the Archives confirming production in 1990 and sale on 13 December 1990 and presentation box

Introduced in 1989 to mark the brand's 150th anniversary, the Patek Philippe Reference 961 combines the most classic complications, a minute repeating and perpetual calendar. It is powered by the Cal. 21''' RMDQ movement, where "RM" stands for minute repeater, "D" for spring detent escapement, and "Q" for perpetual calendar. Its predecessor, the Cal. 21''' RMD, was based on the classic curved bridge layout designed by Victorin Piguet for Patek Philippe.

The project development began in 1985, and the movement made its debut at the Baselworld watch fair in 1986. It is the brand's only modern pocket watch movement to use a spring detent escapement, paired with a helical balance spring that enhances timekeeping precision while minimising mainspring energy loss and system wear. The strong bi-metallic balance wheel perfectly recaptures the features of Patek Philippe pocket watches from a century ago.

Apart from the Cal. 89, the Cal. 21''' is the largest modern pocket watch movement produced by the brand, with dimensions more commonly associated with a deck watch or small carriage clock. A larger size not only gives components greater durability but also allows ample room for the intricate chiming mechanism. The perpetual calendar also incorporates a leap year display and a 24 hour indicator. Hidden quick-set pushers on the case band enable adjustment of both the moon phases display and the entire perpetual calendar system, a design that Patek Philippe has retained from vintage pocket watches to the present day, avoiding calendar confusion caused by independent adjustments.

The silvered dial features sandblasted and matte finishing, giving the monochromatic dial a two-tone appearance and a strong sense of depth. The movement number printed on the moon phases disc at 12 o'clock is another traditional feature. As each handmade vintage perpetual calendar pocket watch has slight variations in the drilling of hand holes and corresponding apertures, every dial is individually fitted to its movement; to prevent mismatching, the movement number is printed on the dial. The 58 mm diameter case perfectly demonstrates the highest standards of Patek Philippe case-making craftsmanship during the 1990s.

According to our research, Cal. 21''' RMD and Cal. 21''' RMDQ movements were assigned movement numbers within the range 866'790 to 866'802. From 1985 to 1990, only two to three examples were produced annually, two of which are permanently preserved in the Patek Philippe Museum. In the nearly 30 years since 1989, only two Reference 961 examples have reappeared on the market.