Visual Description
The 1821 is the midsize Tank Française in 18k yellow gold: a 25 × 30 mm case, polished and brushed, with an octagonal crown set with a cabochon. Bonhams, Fellows and Smith & Singer catalog a silvered dial with black Roman numerals; Antiquorum calls its dials off-white or ivory, and Aguttes cream. The hands are blued steel swords. Bonhams, Smith & Singer and Antiquorum place the secret Cartier signature in the VII. None of the records describes a date window.
Reference Significance
The 1821 sits between the small gold Ref. 1820, 20 × 25 mm, and the large gold automatic 1840, 28 × 32 mm. Its quartz Cal. 157 is the caliber Fellows and Sotheby's give for the midsize steel 2301.
The midsize gold 2466 is the same size and metal, but with a date window and, per Antiquorum, the Cal. 175A.
Historical Context
The 1821 belongs to the first Tank Française range. Fellows sold one on its gold bracelet with papers dated 24 December 1996, and Antiquorum dates two examples to the 1990s. Bonhams, Smith & Singer and Aguttes date others circa 2000, and Antiquorum dates one to the 2000s.
What to Look For
Read the case back for 1821 and an MG serial, and check the 18k marks. The case should measure about 25 × 30 mm; Antiquorum once cataloged one as 25 × 22 mm, which no other record supports. A date window means a 2466. Most examples at auction are on leather straps with an 18k gold buckle; on the gold bracelet, check the links for stretch and the double folding clasp for wear. The quartz movement should run with no battery corrosion.