ROLEX | REFERENCE 6239 'DOUBLE SWISS UNDERLINE' DAYTONA A RARE STAINLESS STEEL CHRONOGRAPH WRISTWATCH WITH REGISTERS, CIRCA 1963

Rolex’s beloved Daytona line was introduced in 1963 with reference 6239 - the first chronograph with an engraved tachometer scale on the bezel. Remaining in production until 1976, it was available in stainless steel, 14k gold, and 18k gold. The present watch features an incredible “Double Swiss Underline” dial, which is seen only in the earliest examples of reference 6239. Bearing the serial number 923’245, this timepiece can be dated back to 1963, which is amongst the earliest examples. Fitted with its correct Mark 1 bezel calibrated to 300 units per hour, it can be easily identified by the 275 units per hour marking nestled between 300 and 250 units per hour – a trait that can only be found on the earliest pieces.

As a result of the larger Cosmograph bezel, Rolex had to duplicate the SWISS stamping in order to make it visible on the dial. There is in fact another “SWISS” designation millimeters beneath the second one, found at the dial’s lower edge by 6 o’clock.

The silvered ‘Underline” found directly below the Rolex Cosmograph signature is believed to be an indication of the transition between radium to tritium. The ‘Underline’ is a characteristic seen on other early Rolex sports models, and today, is often highly desirable for its rarity.

The Valjoux manual winding movement is further stamped ROW, which is seen on watches that were made for the American market.

The present watch is fresh-to-the-market coming from the original family, and has been well preserved over the last six decades. The overall condition, paired with its rarity, makes this a trophy watch for the collector of vintage wristwatches.