As melun wrote , security gates on the airports are ready to use.
To increase importance of the idea surprisingly fast they have written an article which shows how great and successful it is: they stopped 5 foreigners trying to enter japan using fake ID’s, just below that you can read about fingerprint scanners which sometimes don’t work, either because of skin problems or maybe just hardware/software failure, in such case all decision is upon immigration office. If this is supposed to help catching “bad” people i agree with it, but if it’s supposed to extend waiting times and make problems then i don’t agree.
