When using more than 2 sheets of public transportation cards
 (a subway and bus), credit cards of RFID&IC, etc., the Magic
Block Card and various Excess Cards, the Magic Block Card is
used to prevent the occurrence of malfunction and interference
between each Cards and also is used to avoid having unnecessary
 recognition.

1) Insert the card you want to use into the side of your wallet
facing nearest  to the Reader/Writer (the surface you place the card
 incase you enter through the ticket gate of a subway.
2) For the card not to be used, put it into the back end side of your
  wallet.  
3) Insert the Magic Choice Card, having the instruction wording
portion facing to the front, right behind the Card you want to use
 in the same pocket for using it.
4) If you intend not to use all of the Cards kept in the right side
pocket, then insert the Magic Choice Card, having the instruction
wording portion facing to the front, in the up-front of the Card,
then the whole Cards kept in the right side are not recognized.