A breathtaking and incredibly rare piece of horological history: the Rolex Oyster Perpetual "Tru-Beat" Reference 6556. Stamped I.56 inside the caseback with a 138,XXX case serial, this investment-grade medical professional's tool watch dates precisely to the first quarter of 1956. It comes paired on a beautiful, period-correct Swiss-made Rolex 7205 riveted Oyster stretch bracelet with 60 endlinks.

Condition: • Case & Bezel: The 34mm stainless steel Oyster case retains its iconic mid-century lines and smooth steel bezel with honest vintage wear. It shows normal fine surface scuffs and minor hairlines consistent with a 70-year-old untouched survivor. No major dings or egregious gouges. • Crystal: Equipped with a classic domed acrylic Plexiglass crystal in clear, excellent condition with minimal surface marks. • Dial: An absolute standout. It features the rare original "crosshair" layout displaying beautiful, concentric tropical patina along the outer perimeter where the original lacquer has aged naturally over the decades, leaving a stark, gorgeous vintage contrast.

Authenticity & Movement Health: Movement is the legendary, ultra-rare Rolex Caliber 1040. Because many Tru-Beats were converted to standard sweeping seconds during vintage service eras due to parts scarcity, finding an original Caliber 1040 running at this health profile is an exceptional rarity. • Matching Serials: The reference number 6556 matches perfectly between the 12 o'clock lugs and inside the caseback (I.56). The case serial 138### is cleanly visible at 6 o'clock, perfectly matching the mid-1956 production era. • Beat Rate: Timegrapher analysis confirms a flawlessly steady 18,000 VPH (2.5 Hz), exactly correct for this historic movement architecture. • Performance: Running exceptionally strong for a 1950s caliber with a remarkably clean, singular trace line. Amplitude sits healthy at 276 with a near-perfect beat error of 0.1 ms. • Health: Dialed in at a highly stable +17s/d positional rate. The movement shows zero signs of magnetism or erratic timekeeping behavior.

Specs: • Size: 34mm diameter (excluding crown) / 19mm lug width • Movement: Modified Chronometer Caliber 1040 Automatic (with deadbeat seconds complication) • Depth: Vintage standard (100m historically, but assume no modern water resistance) • Power reserve: Approx. 42 Hours • Includes: Watch and authentic Rolex 7205 rivet bracelet only.