Launched in 2010, Walter Lange introduced the F. A. Lange 1815 Moonphase as a tribute to both his great-grandfather Ferdinand Adolph Lange and as a celebration of the brand’s 165th anniversary. To mark the occasion, the firm produced three commemorative timepieces each using their proprietary 18 karat honey gold alloy. In addition to the 1815 Moonphase, which was produced in 265 pieces, A. Lange & Söhne also released a Tourbograph Pour le Mérite and a Lange 1 Tourbillon. The proprietary honey gold alloy is harder (over 300 on the Vickers hardness scale) and more durable, making it more resistant to scratching, while adding a warm hue to the timepiece. On the movement, the typical Glashütte stripes are replaced with a radial finish extending out from the center, matching the guilloché pattern on the dial side.

In addition to the unusual gold alloy, A. Lange & Söhne engineers developed a highly precise moon-phase gear train, which requires no correction to the moon-phase display for 1,000 years as long as the watch is kept wound. The present example, number 248, is preserved in excellent condition and is complete with its guarantee, setting pin, product literature, fitted presentation box, and outer packaging.