Its period of retrograde motion as seen from Earth can vary from 8 to 15 days on either side of inferior conjunction.
From the en.wikipedia.org
Transits of Venus do occur when the planet's inferior conjunction coincides with its presence in the plane of the Earth's orbit.
From the en.wikipedia.org
Later, American astronomer Chester Smith Lyman observed a complete ring around the dark side of the planet when it was at inferior conjunction, providing further evidence for an atmosphere.
From the en.wikipedia.org
By the end of each 15 year encounter Mars was so weakened that around the vernal equinox when Venus, still in an eccentric orbit inside that of the Earth attained aphelion at inferior conjunction.