3051. Rolex. A very fine and rare stainless steel manual wind chronograph bracelet watch with 'Sigma' dial Model: Cosmograph Daytona Reference: 6263 Date: Circa 1975 Movement: 17-jewel Cal.727 manual wind, adjusted to 3 positions Dial: Sunburst silvered 'Sigma' panda, applied polished baton hour markers with luminous dots, black outer 1/5th second divisions, sunken engine-turned subsidiary dials at 3, 6 and 9 for running seconds, 30 minute and 12 hour recording, polished baton hands with luminous inserts, centre white arrow-tipped chronograph hand Case: Brushed and polished tonneau form, screw down back and crown, crown flanked by twin pushers, black fixed tachymetre bezel, No.4128016 Strap/Bracelet: Brushed and polished Oyster link 78360, end links stamped 571 Buckle/Clasp: Signed folding clasp Signed: Case, dial & movement Size: 37mm The Rolex Daytona continues to be among the most sought after of vintage watches on the market today. The bold contrast between the dial colour and the subsidiary dials makes this model instantly recognisable and as such it has long been lauded as a design icon. In 1969 Rolex replaced the first Oyster Cosmograph 6240 with both the reference 6263 and 6265. Although similar in many aspects, the main differentiating factor between the two new references was the choice of bezel. The current lot, reference 6263, features a black aluminium insert with printed tachymetre, whereas the 6265 presented to the market a smooth engraved metal bezel. Reference 6263 dials are characterized by the pronounced 'serif' lettering of the Rolex Oyster Cosmograph signature; additionally, the Daytona signature is omitted on dials meant for models with screw-down push buttons such as this reference 6263. In the dark days of the so-called 1970s quartz crisis, mechanical wristwatches were in danger of losing their popularity in favour of the newly developed quartz movements, seen as the future of horology. High end manufacturers such as Rolex developed different strategies to enhance the perceived intrinsic value of traditional watchmaking. One of these strategies has today become known as the 'sigma dial', a nickname for watches that feature a lowercase letter sigma σ from the Greek alphabet below 6 o clock. This signifies the hour markers being made out of 18K white gold. Introduced in the 1970s, this feature can be found on watches as late as 2003. Nowadays Sigma dials are highly desirable to Rolex collectors the world over for their discreet silvered Rolex signature, their subtlety and their elegance.