A MULE IS COIN MINTED WITH OBVERSE AND REVERSE DESIGNS THAT ARE NOT NORMALLY SEEN ON THE SAME COIN. SUCH COINS ARE MINTED WITH OBVERSE DIE OF ONE COIN AND REVERSE DIE OF ANOTHER COIN. IN THIS COIN 1 RS OBVERSE DIE OF 2011-2019 SERIES STRUCK ON 5 RS 2018 CALCUTTA MINT COIN