With Patek Philippe Extract of the Archives confirming production of the present watch with silvered dial, raised gold hour markers and tachymetre scale in 1941 and its subsequent sale on 28 May 1942.
Preserved in very good overall condition, the present reference 591 stands out by its attractive two-tone dial and the rare retailer signature Casa Masson, one of Patek Philippe's agents in Brazil. The case is very crisp with good definition to the lugs and crisp hallmarks.
Reference 591 is without question one of Patek Philippe's least known chronograph models. According to research, less than 12 examples of this reference cased in yellow gold have appeared in public to date, the exceedingly small production rendering it rarer than any other chronograph model of the period.
Reference 591 differs from all other Patek Philippe chronographs by its generous yet subtle case proportions. Its cylindrical body highlighted by a stepped bezel is crowned with four "bean-shaped" lugs with straight sides. Consequently this reference responds particularly badly to insensible polishing as it quickly loses the angle to the bezel and the edges to the lugs. Thanks to the very special shape of the lugs, this reference is also known as "fagiolino" (Italian for "little bean").
Reference 591 is illustrated in Patek Philippe Wristwatches by Martin Huber and Alan Banbery, second edition, p. 266, pl. 411.