This highly important and exceptionally small, still today the smallest keyless chronometer with one minute tourbillon was created by Fritz-André Robert-Charrue (1908-1983), a celebrated watchmaker of Le Locle. An apprentice of the famous Jämes (better known as James) Pellaton, he later succeeded him as a teacher and director of the Technicum in Le Locle.

The present horological masterpiece brought Robert-Charrue fame, awards and rendered him one of the foremost makers in horology.

In 1927, Pellaton presented the at the time smallest tourbillon in the world with a movement diameter of only 10 1/2''' or 23.6mm, believing this technical prowess could not be surpassed. 18 years later, in 1945, his former apprentice however created an even smaller tourbillon regulator, the present, with a diameter of only 19.7mm or 8 3/4’’’, still today believed to be the world's smallest tourbillon movement.

In his quest for maximal miniaturization, a proof of highest horological skills, Robert-Charrue must have started the manufacture of the watch as early as 1939 or 1940, completing it only five years later, in 1945.

The movement is exceptionally well finished, its plates are maillechort, a strong, non-corrosive, easy to work with alloy consisting of copper, nickel, zinc, and sometimes lead. The entire carriage has a diameter of only 8mm, the width of arm and rim 0.5mm, the thinnest part of the rim a mere 0.28mm. The escapement is a so-called mixed lever escapement, also known as tangential. The smallest jewel has an outside diameter of only 0.6mm.

Five of the miniature tourbillons known to date in chronological order:

1876-77 Ernest Guinand, 31.9mm diam.
1927 Jämes Pellaton, 23.7mm diam.
1945 F.-A. Robert-Charrue, 19.7mm. diam, the present
1947 Omega, 30mm diam.
2020 Bulgari, 22mmx18mm

Appearing only for the second time at public auction, of extraordinary rarity, quality and importance, this horological masterpiece is among the most significant timepieces to be offered at auction in recent years.