Registration Link: http://www.digimonrpg.com/register/intro.aspx
Accept the Terms
First KSSN: If you get an "name check" error, that just means you have to find a real kssn that matches with the name.
Second KSSN: if you get a "name check" error, then that just means your kssn is too old. Try using a younger dated one.
Final Step: Use this "서면" for the zip code.