Tropical 1951 Longines Sei-Tacche (Ref. 5413 10)

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. 5413 10 brings all the hallmarks that collectors seek: a 33mm stainless steel case with drilled lugs, a warm silver 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. SPECS Stock # LGSST541310 Brand Longines Style Sei-Tracche Model 5413 10 Serial 83XXXXX Size Men's / Unisex Material Stainless Steel Dial Beige "Tropical" Millimeters 33 Strap 2pc Leather Strap CASE & BRACELET The excellent case features long lugs extending its size beyond its diameter measurements and retains crisp finishing and edges throughout, showing no notable wear and light evidence of being previously polished. The crown is believed to be original to the watch. The distinctive 6-notch case back is in excellent condition with light wear present and is adorned with an engraving of initials that read "R.M.H." Additionally, the back of the top left lug bears a matching engraving to the case back, corroborating the originality of the watch. The watch comes supplied on a 2pc black leather strap. DIAL & HANDS The original dial has achieved a charming peachy-beige tropical patina throughout and remains in wonderfully preserved condition for its age, exhibiting only gentle marks and wear. The radium filled arrow markers and numerals have achieved a charming beige coloration, with some darker spots, and exhibit nominal degradation when inspected under UV light. The original alpha hands were previously restored with radium and feature a subtle cream coloration. The blued seconds hand introduces a welcomed touch of color to complete the watch. ACCESSORIES None. The watch is keeping time; the service history is unknown. A movement service can be purchased upon request.