1946 Inverted S Mint Mark
In 1946 there were three different
mintmark styles used by the San
Francisco mint.  These styles are the
Sans Serif, Serif, and Ball Serif.  The
Ball Serif is scarcer than the other two

This die variety is a 1946 S Lincoln
Cent with an inverted mintmark.  The
mintmark was actually struck upside
down.  This is the only known inverted
mintmark in the Lincoln series, and it
can only be seen on the Ball Serif style
1946 S cents.  

This variety is extremely rare.  It is
recognized by Coneca and Wexler.  
ANACS will certify this variety.  

Images courtesy of BJ Neff