Sei Tacche

The Longines Sei Tacche is sought after for its ties to mid-20th-century military and field watches, originally designed for reliability in demanding conditions. Its name, meaning "six notches," refers to the distinctive six-notch caseback, an early water-resistance innovation that collectors prize. Among vintage Longines, the Sei Tacche sits apart for its utilitarian roots and understated elegance, making it a compelling option for those drawn to authentic tool-watch heritage.

Most Sei Tacche examples feature a 38.5mm stainless steel case—unusually large for its era—paired with hand-wound Longines calibers like the caliber 12.68Z or caliber 23M. Dials vary: some carry luminous Arabic numerals and blued hands, while others have more formal layouts. Reference numbers differ by dial design and caliber, with early wartime models often commanding a premium, especially if paired with original radium lume and signed crowns.

Condition is paramount: untouched dials, crisp engravings, and correct period crowns drive value. Water resistance, while innovative at the time, should not be relied upon today, so prioritize case integrity over claims of modern sealing. The Sei Tacche is less prone to rampant counterfeiting than some vintage icons, but dial redials and replaced crowns are common—examine these details closely when comparing examples.