It’s not unusual for foreign residents in Japan to be asked for identification. 

It can be problematic for police officers to make such requests because, while foreign residents are required by law to carry their residence cards with them at all times, certain conditions must exist before they demand to see some identification. The simple fact that foreign residents don’t “look” Japanese in and of itself isn’t sufficient grounds.   

Well … imagine if you are subjected to one of these seemingly arbitrary ID checks if you’re a Japanese citizen?