Founded in 1860 by Giovanni Panerai (1825-1897), Officine Panerai specialized in producing high precision instruments for the Royal Italian Navy, ranging from wristwatches to navigation tools. In the early 20th century, Panerai created Radiomir, a luminous-based powder that was eventually patented on 23 March 1916. The firm’s Radiomir technology allowed for many strides in the military industry. When applied to the dial, the compound allowed the viewer to tell the time in any weather condition by glowing in the dark. Panerai produced its first Radiomir prototype in 1936.
Originally purchased by the original owner over thirty years ago and consigned at auction by a family member in 2013, the present reference 3646 is one of the most impressive examples to grace the auction market, due to its bullet-proof originality. Since its introduction, the model always had specific technical requirements. The cushion-shaped case was 47 mm. wide with soldered curved wire lugs, a screw down "onion" crown was present and the case back had 12 sides. The black dials were coated with half Arabic and half Roman luminous numerals on black lacquer background and only marked "SWISS MADE" below 6 o'clock. Furthermore, the 16 lines caliber 618 Cortébert movements were finished by Rolex and decorated with the Geneva stripes.
The present watch most notably belongs to the last batch of reference 3646s and displays an "Error-Proof" or "California" dial and does not display any Rolex signatures or hallmarks - typical of this tight production run. Furthermore, it has a thinner case compared to earlier types and low bezel.
The present watch belongs to an order of 720 reference 3646 pieces made in mid 1943 but delivered in three lots. The first batch consisting of watches numbered 260400 - 260695 was delivered in 1943, the second group with serials 260696 - 260849 in early 1944, and the last lot featuring case numbers 260850 - 261120 in the second quarter of 1944. With few exceptions, all of these watches were requisited by the German Navy.
According to folklore, a small group of "Error Proof" reference 3646 dials were originally made for high ranking Navy officials. However, before the liberation of Florence in early August 1944 by the British 8th Army, the German Army had visited the G.Panerai & Figlio workshop and confiscated all remaining watches, instruments and machines. Subsequently, the loot was shipped to the Arturo Junghans watch factory on the island of La Giudecca in Venice. At the time, Venice was the center of all underwater warfare operations. In the early 1990s, the Arturo Junghans factory was transformed into lofts and a theatre. When the various buildings were cleared, the workers found dozens of anonymous Panerai sandwich dials, Rolex Error-Proof dials with missing dial feet and many so-called "painted brass dials" which had been produced by
Junghans to replace the Error-Proof dials. In addition, they also found around 30 NOS (New Old Stock) Ref. 3646 featuring Error-Proof dials, still in their original cardboxes. Given its condition, with untouched movement screws, etc., the present watch could be one of the then discovered pieces.
The present watch is preserved in most impressive condition, having never been altered throughout its lifetime. The luminous material remains original, and has aged with warm patina. The movement too, does not display any signs of heavy wear. With case number 261078, the present watch is part of the last iteration of Ref. 3646 featuring a slimmer middle case (5.4 mm vs. 6.3 mm), a low bezel and a patented Rolex Error-Proof dial. Rolex filed the patent application for this type of dial in May 1941 (CH221643). The entire batch was anonymized by Rolex by removing the Rolex stamps from the casebacks and using
unbranded movements. This was done to conceal the manufacturer of the watches. Until today, only 22 pieces of this type have surfaced.
The Rolex Error-Proof dial is commonly referred to as "California dial". The nickname goes back to a dial refinisher from California who in the late 1980s specialized in restoring Rolex Bubbleback dials.
