With Patek Philippe Certificate of Origin dated 25 May 1895 and Extract from the Archives confirming production of the present watch with "demi-découverte" or half-openface case in 1890 and its subsequent sale on 28 May 1895. Furthermore accompanied with the original fitted presentation box containing a spare crystal.
The present watch is fitted with the rare "demi-découverte" or half-openface case form featuring a second "snap on" style bezel, a water-resistant variant consisting of five pieces. It furthermore uses a very unusual stem winding system, invented by O. Courvoisier, English patent No. 1114 of 1873.
To the best of our knowledge, the present watch is the only example of such a half-openface watch cased in silver and featuring the Courvoisier winding system known to exist to date, the rarity enhanced by the presence of the original certificate and box.
The Courvoisier system was evidently used by Patek Philippe as an experiment in an exceedingly small number of watches. The system works by the shifting of a large wheel which engages with a further wheel on the centre wheel arbor for hand-setting when the crown is turned anti-clockwise, when the crown is turned clockwise the wheel disengages and winds the mainspring. Two other examples, including watch no. 55948 sold to Prince Ghika of Albania on 1 March 1884, are illustrated in Patek Philippe by M. Huber & A. Banbery, p. 122, pl. 43 & 44.