Vénus 103 CHR

	Brand:	Vénus
	Family:	Unknown
	Height:
	Jewels:	15
	Reserve:	47 hours
	Frequency:	18,000 A/h
	Winding:	Hand winding
	Diameter:	23.3 mm (10.5 ligne)
	Complications:	Cam Switching Chronograph, Chronograph, Monopusher Chronograph
	Hands:	Central 60 Second Chronograph Hand, Central Hour Hand, Central Minute Hand, Small Seconds Hand at 6:00

Distinguishing Technical Characteristics
Hand-Winding Clockwise Balance Cock Indexed Regulator Balance at 3:00 Barrel at 10:30
Production: 1933 –
1910s	1920s	1930s	1940s	1950s	1960s	1970s	1980s	1990s	2000s	2010s	2020s

Cal. 103 CHR was the first chronograph movement produced by Vénus. Introduced in 1933, it was based on their 10.5 ligne round movement family, which began with Cal. 75 and was widely produced in the 1920s and 1930s. It is a monopusher movement with a running central chronograph hand and no stop or counter mechanism.

Cal. 103 CHR is unusual in many ways. It has no counters or start function, with a continuously-running central chronograph hand reset on demand using the pusher. It was conceived without the conventional column wheel, relying instead on simple cams to reset the running seconds hand. The pusher was co-axial with the crown. A similar mechanism was used on Cal. 131 CHR, a tonneau-shaped movement produced later in the 1930s.

Later iterations of a chronograph on Cal. 103 appear quite different, with a column wheel and separate pusher at 4:00. It is likely that these, although still called Cal. 103 CHR, are a completely different design.

More detail on the history of Vénus is available in the Grail Watch article, “The Rise of Vénus, Legendary Chronograph Maker“