I don't think they're proposing to block the PROTOCOL. (Is it even possible to reliably distinguish Tor traffic from other encrypted traffic?) Rather, I think

I don't think they're proposing to block the PROTOCOL. (Is it even possible to reliably distinguish Tor traffic from other encrypted traffic?) Rather, I think they're proposing to block all packets being sent to known Tor end-nodes. Of course, miscreants can get around this by bouncing their packets off a relay outside Japan. This will actually HELP Japanese criminals who go to the trouble of using a relay. When they cause trouble, the first response of the authorities will be, "This is the work of foreign criminals." (A common scapegoat, alas.) "It can't possibly be coming from Japan, because we've blocked Tor." (and we're certainly not going to admit that our firewall leaks)