I don’t know a whole lot about these trading cards, unfortunately. I just picked them up from a Yahoo Japan auction; Google translates the listing title as “Superman card front Pachigaikingu Z.” It’s an uncut sheet of 16 trading cards with a character that looks an awful lot like Superman, except he has a Z on his chest. Each card, if it were cut down, would measure about 1-3/4″ wide by 3″ high, meaning they’re bigger than Menko cards. Each card features a different color image of Superman (with a Z), including scenes of him fighting robots and giant monsters and flying through the city. One of the cards shows him standing with a character that looks an awful lot like Captain Harlock.
The backs are printed in one color and I have no idea what they say.
If you have any information about this item, please contact me!