Swiss watchmaker Longines presents ULTRA-CHRON, an extremely accurate watch model inspired by the brand’s rich heritage of producing high-beat movements for over 100 years. More precise than a chronometer, this timepiece houses a high-beat self-winding mechanical movement with an oscillating frequency of 10 beats a second.

Introduced in 1968, the Longines Ultra-Chron Diver was the first dive watch to be equipped with a high-frequency movement. At the time, the brand had already established itself as a pioneer in high-frequency technology.

In fact, the brand created its first high-frequency timekeeping device to measure precisely 1/10th of a second as early as in 1914. In 1959, Longines developed the first high-beat movement for a wristwatch, an observatory chronometer that set new records in terms of accuracy.

The new Longines Ultra-Chron watch is inspired by the aesthetic codes as well as the professional dive features of the 1968 model. It features a unidirectional rotating bezel as well as a screwed-in caseback and crown. It also offers great legibility and is water resistant to 30 bar (300 meters).

The Longines Ultra-Chron’s instantly recognizable 43mm cushion-shaped steel case is fitted with a diving bezel that boasts a sapphire insert with luminescent accents. The eye-catching black grained dial features a white minute track with alternating Super-LumiNova®-coated batons and rhodium plated appliques.

The original Ultra-Chron logo is visible on the dial and embossed on the caseback. The new Longines Ultra-Chron has a distinctive red minute hand which, like the hour hand, is coated with Super-LumiNova® for optimal legibility.

The new Longines Ultra-Chron watch is equipped with the self-winding calibre L836.6, a high-frequency “in house” movement. Its silicon balance-spring oscillates at 36,000 beats per hour (10 beats every second).

From 1959 onwards, Longines made use of the high-beat-movements to increase the accuracy of its watches. Thanks to a reduction of the disruptive effects of shocks or of changes in the position of the movement, the high-beat movement proves to be more stable.

The accuracy of the Longines Ultra-Chron is confirmed by its certification as an “ultra chronometer” by TIMELAB, an independent testing laboratory in Geneva. This designation goes beyond the usual “chronometer” certification.

The “ultra-chronometer” qualification process tests the watch head and subjects the finished product to a15-day testing period during which the watch is submitted to a series of tests at three temperatures, 8°C, 23° C and 38°C, confirming that it meets the strict precision criteria (ISO 3159:2009 standard).

The Longines Ultra-Chron is available with a choice of a leather strap or a steel bracelet and it is delivered in a special presentation box containing a black NATO strap crafted from recycled material.

The History of High-Frequency Watches Made by Longines

More than 100 years of experience in manufacturing high-frequency timepieces has made Longines the leading expert on professional timekeeping and in sports watches. The fast-beating movements are capable of measuring 1/10th or 1/100th of a second. In addition, they have proven to be extremely accurate. Over time, the iconic Swiss company has built a wide variety of high-beat stopwatches, chronographs and chronometers.

1914: Stopwatch with 5 Hz high-frequency movement and split-second hand [CAL. 19.73N]

As early as 1914, Longines used high-frequency movements in its handheld stopwatches for the timekeeping of sporting events to measure 1/10th of a second. Driven by the calibre 19.73N with a balance wheel oscillating at 36,000 beats per hour, this chronograph proved very successful in sports, military and medicine.

The model pictured was equipped with a split-second hand, a modification introduced in 1922. To improve the reading of 1/10th of a second, the chronograph hand rotates once around the dial in 30 seconds. The 15-minute counter is placed on the auxiliary dial near 12 o’clock.

1916: Stopwatch with 50 Hz high-frequency movement to measure 1/100th of a second [CAL. 19.73N]

In 1916, Longines was capable of measuring 1/100th of a second. Based on the modified calibre 19.73N, the engineers in Saint-Imier enhanced the speed of the balance to a rate of 360,000 beats per hour–and thus enabled the exact reading of 1/100th of a second. To achieve this, the chronograph hand flew over the dial in just three seconds to its starting position.

The scale on the periphery of the dial was divided into very small steps of 1/100th of a second. An instantaneous minute counter was placed at 12 o’clock and could measure up to three minutes.

1938: High-frequency skiing timer (5 Hz) with split-second hand [CAL. 24 LINES]

As sporting events became more important, Longines was appointed Official Timekeeper on numerous occasions. In 1938, it developed a larger and more accurate movement: the 24 lines. This chronograph was constructed on the basis of a navigational chronometer (cal. 24.99).

The timer for ski races pictured here (from 1939) ticked at 36,000 beats per hour to measure 1/10th of a second. The chronograph hand made one rotation in 30 seconds, which helped read the fractions of a second.

Equipped with a second split-second hand and a 30-minute recorder, this professional stopwatch with three pushers was encased in Staybrite steel. The movement was adjusted to three positions and gained special notice at the Observatory of Neuchâtel for its high accuracy. Longines built a variant of this calibre to measure 1/100th of a second.

1957: Professional high-beat and split-second chronograph to time 1/10th of a second [CAL. 260]

To improve the 24-line calibre of 1938, Longines launched a chronograph of the same size in 1957 with a 30-minute counter and a system of stopping the balance. This professional instrument still had a minute and hour hand, but was also able to measure 1/10th of a second thanks to its high-frequency movement (36,000 vibrations per hour).

It was equipped with a flyback function and a split-second hand. The pictured model from 1966 has a special chronograph hand with a so-called nonius-scale: at its extremity there is a rack with nine “teeth” that indicate the end of the hand.

When the hand is stopped, one of the “teeth” stops exactly in line with one of the “seconds” marks around the dial. The number at the base of this “tooth” indicates the number of tenths of a second.

1959: First high-frequency wristwatch Observatory Chronometer [CAL. 360]

In the 1950s, Longines was convinced that there was a need to increase the scientific efforts to maintain its competitive edge.

Following the technical drawings of August 1958, Longines was ready to present the first high-frequency movement for a wristwatch in 1959: the calibre 360, oscillating at 36,000 beats per hour, handmade and fine-tuned for Observatory Chronometer Competitions. This technical milestone was built in a series of 200 pieces from 1959 to 1963.

The rectangular movement improved the accuracy considerably, and it took first and second place in the accuracy competition at the Observatory of Neuchâtel in 1961 and the following year, claimed first, second and third places. The daily deviation was around or below 1/10th of a second.

1966: Ultra-Chron, the accurate high-beat wristwatch [CAL. 431]

In the 1960s, Longines’ engineers worked on a mechanical movement that matched the accuracy of the new electronic watches. Thanks to their experience in timekeeping and in Observatory Chronometers, they knew that high-frequency watches were more consistent between the vertical and horizontal positions and suffered less drop in amplitude over a day, making them more accurate. The obstacles were lower power reserve and lubrication problems.

Longines found the solution in the calibre 431 (with patented dry lubrication) and guaranteed an amazing accuracy of one minute a month, or two seconds a day. Being far more accurate than a chronometer certified by the COSC (Contrôle Officiel Suisse des Chronomètres), the model was named Ultra-Chron.

Longines registered the name in October 1966. The first Ultra-Chrons were sold in the United States in December 1966.

1968: Ultra-Chron Diver, the first high-beat watch under water [CAL. 431]

In 1967, Longines drew a sporty version of the Ultra-Chron: a diver’s watch with a bright-red minute hand, water-resistant to 200 metres. In early 1968, it was the first high-frequency diving watch, and probably the most accurate, driven by the unique calibre 431.

As with all the Ultra-Chron models, Longines guaranteed an accuracy of one minute a month, which converts to two seconds a day. The tonneau-shaped watch was fitted with a calendar mechanism and a turning bezel, which enabled divers to determine their immersion times. To ensure legibility, even in murky water, the index marks on the dial hand, the triangle on the bezel and even the tip of the seconds hand (in the first series) were filled with tritium.

Technical details

Model: Longines Ultra-Chron

Reference numbers
L2.836.4.52.9
L2.836.4.52.8

Movement
Calibre L836.6
High-frequency mechanical self-winding movement
11½ lines, 25 jewels, 36’000 vibrations per hour
With silicon balance-spring
Power reserve: around 52 hours

Functions
Hours, minutes, seconds

Case
Diameter: 43.00 mm
Thickness: 13.60 mm
“Cushion” shape, stainless steel
Unidirectional rotating bezel with sapphire insert, Super-LumiNova®
Sapphire glass box with several layers of anti-reflective coating on both sides
Screwed crown and screw-down case back
Special engraving on the case back with the “Ultra-Chron” logo and “ULTRA-CHRONOMETER officially certified” mention
Water-resistance: To 30 bar (300 meters)

Dial
Black grained
4 applied silver indexes with Super-LumiNova® underneath
Original applied “Ultra-Chron” logo

Hands
Rhodium-plated (hours, seconds), red (minutes)
Super-LumiNova® (hours, minutes)

Bracelets/ Straps

• Reference L2.836.4.52.8: Brown leather strap with buckle and an additional black NATO strap made of recycled material. Sold in a special wooden watch box with a tool to change straps.
• Reference L2.836.4.52.9: Stainless steel bracelet with double safety folding clasp and push-piece opening mechanism and an additional black NATO strap made of recycled material. Sold in a special wooden watch box with a tool to change straps.

Certification
“Ultra-Chronometer” officially certified by TIMELAB Geneva