Longines Ultra-Chron Automatic Square Case Ref. 7824-1
Dress Watch (High-Frequency) · Longines (Swatch Group parentage currently, but independent manufacture during this era). Luxury tier with a historic reputation for chronometric precision.
Period: Modernist/Late 1960s. Indicators: Tonneau-style square case, integrated-look lugs, and high-frequency 'Ultra-Chron' branding typical of the 1967-1975 era.
Type
Dress Watch (High-Frequency)
Brand
Longines (Swatch Group parentage currently, but independent manufacture during this era). Luxury tier with a historic reputation for chronometric precision.
Movement
Automatic, high-frequency Caliber 431. Frequency: 36,000 bph (5Hz). Power reserve: ~40 hours. 17-25 jewels depending on specific iteration. Instantaneous date change.
Dimensions
33mm width (excluding crown), 33mm height, 41mm lug-to-lug, 18-19mm lug width. Wears larger due to the square footprint.
Description
The Longines Ultra-Chron was the brand's response to the quest for ultimate mechanical accuracy, launched to commemorate Longines' 100th anniversary. This square-cased variant represents the bold, geometric design language of the late 60s. The 36,000 bph movement provides a sweep second hand that is significantly smoother than standard mechanical watches of the time.
Key Features
36,000 bph 'Hi-Beat' movement, signature Ultra-Chron lightning bolt logo, unique 4:30 date window orientation, and the rare square-tonneau case geometry.
Dial Description
Silver sunburst dial with applied baton indices. Features the applied Longines winged hourglass logo at 12 and the 'Ultra-Chron' lightning bolt logo at 6. Date window between 4 and 5 o'clock. Straight baton hands.
Case Material
Stainless steel. Features a combination of brushed horizontal finish on the face and polished sides. The lugs are hidden/sculpted into the case body.
Crystal Type
Acrylic/Hesalite. Domed and square-fitted. Visible surface scratches and minor crazing consistent with age.
Bezel Details
Fixed integrated bezel as part of the monobloc or two-piece case design. Polished finish surrounding the crystal aperture.
Crown & Pushers
Push-pull crown, partially recessed into the case side to maintain the streamlined square silhouette. Original crowns usually feature the Longines text or logo.
Bracelet or Strap
Aftermarket or period-correct five-link stainless steel 'brick' style bracelet. Brushed finish with a folding clasp.
Caseback Details
Solid stainless steel screw-down or snap-on caseback. Usually features the 'Ultra-Chron' logo and serial numbers on the interior or exterior.
Movement Type
Automatic, high-frequency Caliber 431. Frequency: 36,000 bph (5Hz). Power reserve: ~40 hours. 17-25 jewels depending on specific iteration. Instantaneous date change.
Water Resistance
Originally 30m (splash resistant); currently considered non-water resistant due to age and square crystal seating.
Origin & Provenance
Swiss Made. Manufactured in Saint-Imier, Switzerland. Features a significant in-house movement (Cal. 431).
Age Estimate
Circa 1968-1972. Characterized by the high-beat movement era and the specific 4:30 date placement.
Cultural Significance
Represents the pinnacle of high-frequency mechanical watchmaking before the Quartz Crisis. It remains a cult favorite among collectors who appreciate 'sleeper' vintage pieces with high-grade engineering.
Condition Notes
Good vintage condition. The dial shows minor oxidation/staining near the edges. The crystal has several surface scratches that could be buffed. The case shows 'honest' wear with softening of the brushed grain. Overall Grade: Good.
Value Estimate
$600 - $1,200 USD. Value is driven by the movement's health and the condition of the specific square crystal, which is difficult to replace.
Care & Maintenance
High-beat movements require specialized lubrication because of the 5Hz speed. Recommend servicing every 5 years by a vintage specialist. Avoid water entirely due to aged gaskets.
Similar Watches
King Seiko Hi-Beat 4502, Zenith Respirator 'Kennedy', Girard-Perregaux Gyromatic HF, Grand Seiko 61GS.
Interesting Facts
When released, Longines guaranteed the Ultra-Chron to be accurate to within a minute a month, which was extraordinary for a non-quartz mechanical watch in the late 1960s.