The shitajiki below are trading shitajiki. They were sold by boxes in Japan. They are just like any other shitajiki in size and thickness. They have numbers on them, this is where they get "trading" from. So people can try to collect all the numbers. There are 60 regulars and 6 specials in all. A single shitajiki contains two numbers, for instance, the front will be #01 and the back will be #02. Please email me if you have any confusion.