Tropical 1948 Longines Sei-Tacche (Ref. 23788) Military Dial

Longines is one of the oldest continuously operating watch manufacturers in the world, with roots dating back to 1832. Over that immense period of time, the brand has crafted some truly incredible and incredibly accurate timepieces. In fact, it's one of the reasons Longines is the official timekeeper of the Kentucky Derby, where accuracy is paramount. 

Among vintage Longines, few models capture the imagination of collectors quite like the “Sei-Tacche.” Produced in the 1930s and 1940s alongside the earlier “Tre-Tacche,” these watches earned their names from their distinctive casebacks, six notches for the Sei-Tacche, three for the Tre-Tacche, engineered for a tighter seal and requiring specialized tools to remove. Beyond this functional innovation, the Sei-Tacche has become a cult favorite, celebrated for its uncompromising simplicity and its place as one of the earliest true “tool watches” before the category even had a name.

This 1951 example ref. 23788 brings all the hallmarks that collectors seek: a 33mm stainless steel case, a warm military-style dial with bold radium-lumed Arabic numerals, a red 24-hour scale for a touch of color, and a refined blue steel handset. The six-notched caseback and rugged construction speak to Longines’ wartime focus on reliability and resilience, making these pieces both historically significant and incredibly wearable today.

For collectors, the Sei-Tacche represents more than just a vintage Longines; it embodies the brand’s legacy of precision and durability, qualities that established its reputation in both civilian and military circles. With its understated aesthetics, robust build, and undeniable historical importance, the Sei-Tacche remains one of the most compelling entry points into serious vintage Longines collecting.