There is something incredibly appealing about the early hand-wound Rolex Daytonas, especially when they come with a beautifully contrasting black dial. This reference 6265 has everything we love about the original Cosmograph: balanced proportions, purposeful details and a character that has only become more attractive with age. And then there is that wonderful Black Sigma dial, a subtle detail that makes this particular example especially interesting. Dating to 1975, this stainless steel Daytona features the distinctive MK2 Black Sigma dial with contrasting white registers and crisp white printing. At six o'clock, the small Greek sigma symbols flank the T SWISS T signature, indicating the use of precious-metal hour markers and hands, in this case white gold. It is one of those understated details that collectors have come to appreciate in these early Oyster Cosmographs. The dial presents beautifully, with finely textured subsidiary registers and warm, gently aged tritium hour plots. The familiar three-register layout is framed by the engraved stainless steel tachymeter bezel, giving the watch its unmistakable early Daytona appearance. The 37 mm Oyster case retains well-defined proportions, with light signs of wear consistent with its age. The steel bezel remains attractive, with clearly legible engravings and some small marks from use. Early MK1 screw-down chronograph pushers complete the classic appearance. The watch is fitted with a Rolex Oyster bracelet reference 78350 with 571 end links, a natural match for the sporty character of the Cosmograph. Inside beats the celebrated manually wound Rolex calibre 727, based on the Valjoux 72 chronograph movement and fully serviced by an experienced professional watchmaker. For us, the beauty of this Daytona lies in its restraint. No colourful accents or unnecessary details, just a wonderfully balanced black-and-white dial, a steel bezel and one of the great hand-wound chronograph designs. Specifications: Rolex Oyster Cosmograph Daytona, Ref. 6265 Serial 396xxxx, 1975 Stainless steel Oyster case, approximately 37 mm, acrylic crystal MK2 Black Sigma dial with white text, white-gold markers and contrasting white registers Engraved steel tachymeter bezel and Early MK1 screw-down pushers Rolex Oyster bracelet Ref. 78350 with 571 end links Manual-winding Rolex calibre 727 Fully serviced by an experienced professional watchmaker One-year mechanical warranty Fully insured worldwide shipping included Historical Context Introduced in the early 1960s, the Rolex Cosmograph evolved into one of the most recognisable chronographs in watchmaking. References 6263 and 6265 represented the final generation of manually wound Oyster Daytonas, remaining in production until the arrival of the automatic Daytona in 1988. While the 6263 featured a black acrylic bezel insert, the 6265 retained the engraved metal tachymeter bezel, giving it a particularly clean and understated appearance. The Sigma dials belong to a fascinating chapter of 1970s Swiss watchmaking. Their discreet markings highlighted the use of gold components at a time when the traditional mechanical watch industry was increasingly challenged by new technologies. Today, they remain a small but meaningful detail for collectors who appreciate the many variations of the early Cosmograph.