Off-Center Strike
The image to the left is an example of a 2000
Lincoln Cent that has been struck off-center.  

An off-center strike is a result of a coin being
struck outside the collar.  Unlike a
broadstrike, the
image is not in the center of the coin.   The result
of the punch usually  results in a coin that is not
circular.  

Off-centers can vary in degrees of how far
off-center they are struck.  Collectors differ in the
type of off-centers they desire.  However, coins
with full dates are usually more desirable than
those without dates, or missing digits.