Swiss gold split seconds chronograph with recorder Circa 1921

Gold split seconds chronograph by Vacheron & Constantin
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A beautiful and extremely rare Swiss gold keyless winding split seconds chronograph with recorder, circa 1921. This watch was completed in June 1921 and sold on May 29, 1923, to Mr E. E. Robert, New York.
Highly complicated precision lever movement  (ébauche by Victorin Piguet, Le Sentier, Vallée de Joux), lever escapement, index regulator with swan neck spring and micrometric screw, eight adjustments, fine adjusting device, split seconds chronograph. Silvered dial with Arabic numerals, subsidiary seconds at 6, Breguet style hands, and three horological complications: 1/5 second chronograph (activated by the single round push piece located on the winding crown) Split seconds (activated by the rectangular push piece located on the case band at 11 o’clock) Instantaneous 30 minute recorder (subsidiary dial at 12 o’clock). Plain 18K yellow gold round shaped case. Dial, case and movement signed.
Accompanied by the Extract from the Archives, dated November 10, 1994, that mentioned this watch was made in 1920 and sold in 1923.
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Diameter: 46 mm
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Signed: Vacheron & Constantin, Genève Suisse
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Ébauche, Incomplete watch movement.
Until about 1850, the ébauche consisted only of the bottom plate, bars, fusee and barrel. The old Genevese watchmakers called the ébauche le blanc, i. e. the blank.
In the early 19th century, the ébauche consisted of two plates with pillars and bars, the barrel, fusee, index, click and ratchet wheel, and a few assembling screws. These parts were all roughly filed and milled. The steel and brass parts were manufactured in special workshops. The ébauche was finished in the finishing shop (Comptoir d’établissage).
The modern ébauche is a jewelled or non jewelled watch movement without its regulating organs, mainspring, dial or hands.