Accounts and IC Cards FAQ
ECS-ID(Accounts for Students)
It is not necessary to activate it again as long as you remember the password. But if you don't remember it, you can set a new password by activation.
And also, please set email forwarding of Student E-mail (KUMOI) to your regular email address as well. You can set email forwarding on the same URL as for activation.
Activation and email forwarding setting website :