It is pretty obvious which ones are the toilet slippers.

Japan has lots of oddities that help make it such a wonderful place to visit and there is a laugh around every corner. Toilet slippers are probably common in societies that take their shoes off when inside. In Japan this tradition originates with tatami mats being used as the main flooring and it would easily scuff and become dirty if everyone wore shoes through the house. To make sure you don’t get your house slippers mixed up with the toilet slippers you might find they have big pictures and writing on them. Concentrate when leaving the toilet and make sure you do the changeover or you may find yourself embarrassed when someone notices your mistake. I liked these one’s so much I bought them for the hotel.