Based on the 5726/1A reference, this replica nautilus 57261A blue 40.5mm 69273 delivers the annual calendar complication in a dark blue dial with stainless steel case at 40.5mm. The 5726/1A is one of the most technically dense Nautilus models Patek Philippe has produced, packing day, date, month, moon phase, and a 24-hour indicator into a case only half a millimeter larger than the standard 5711. The blue dial carries the same horizontal embossing found on every Nautilus, but the calendar apertures and moon phase subdial add layers of visual information that the time-only models lack.

Technical Overview

• Reference: 5726/1A
• Case diameter: 40.5mm
• Case material: stainless steel
• Dial: blue with horizontal embossing
• Functions: annual calendar (day, date, month), moon phase, 24-hour indicator
• Movement: automatic
• Crystal: sapphire

The annual calendar mechanism recognizes the difference between 30 and 31-day months, advancing the date correctly through the entire year with just one adjustment required each March. The moon phase tracks the 29.5-day lunar cycle with enough precision to stay accurate for over a century before needing correction. Unlike a perpetual calendar, the annual version keeps the movement thinner and the service intervals more manageable.

Inside the Movement

Patek Philippe selected the Caliber 324 S QA LU for this reference, integrating calendar and moon phase modules into the same slim automatic base. The day and month display through twin windows at 12 o’clock, the date appears between 4 and 5, and the moon phase subdial occupies the 6 o’clock position. All five functions update themselves at midnight without manual intervention. The blue dial adds depth to the calendar windows, creating a tonal harmony between the embossed surface and the printed aperture text. See other complicated Nautilus options in the full Nautilus range, or consider the Ladies Nautilus 7118 for a different take on the collection.

What Sets It Apart

This particular listing offers the blue dial 5726/1A as a distinct option from other blue Nautilus references in the catalog. The annual calendar transforms the Nautilus from a luxury sport watch into a genuine complication piece that competes with dedicated dress watches on mechanical sophistication. Steel construction keeps it within the sporty ethos of the Nautilus family rather than the precious-metal formality found in the Complications line. The blue dial ensures this reference remains visually connected to the most iconic Nautilus color tradition while adding substantial horological depth. This replica nautilus 57261A blue 40.5mm 69273 represents the intersection of sport-watch design and calendar watchmaking in one package.