Rolex Day-Date President 6511

The Reference 6511 is a historically monumental timepiece, representing the inaugural Day-Date model introduced at the Basel Fair in 1956. Its technical specification is a 36mm Oyster case in 18k gold with a fluted bezel. It was the first automatic, waterproof chronometer to display both the day of the week spelled out in full and the date. It was powered by the newly developed Caliber 1055. However, this initial movement had a technical flaw in the calendar mechanism that led to a very short production run of about one year. This makes the 6511 exceedingly rare and significant as the direct progenitor of the entire Day-Date lineage, complete with early design cues like gilt dials, alpha hands, and a “bubble back” style case.