Register, and license issued
In Japan, there are 2.3 million Nihonto presently registered. And more than 10,000 Nihonto are newly registered every year. It is common that unregistered swords are hidden in an old house, and found after the owner deceased by the family member. If that case happened in your family, you need to contact the crime-prevention section of the district police and make a report of finding unregistered Nihonto. This is the primary step that will enable the finder to attend the "Toroku-shinsa" or evaluation meeting for issuing the license, called "Juho-token-rui-torokusho" or in short, "Torokusho".
What needs to be evaluated in order to issue the license is if the sword was made by authentically traditional way using proper materials. Antique swords and contemporary sword made by registered smiths are eligible to obtain the license. In another word, only Nihonto can be licensed.
Mass produced, so called, "during-war-swords" and foreign made swords are not eligible. If the evaluation results in rejection of issuing the license, the swords gets confiscated.
The license is issued by the Prefectural Education Board. It is not the certificate of authenticity. It only states a few description of the sword. It is the blade to be registered, not the owner. The license has to be attached to the sword at all time. The owner usually keeps it in the "Shirasaya" or wooden made storage case.
All registered Nihonto are granted as the antique or art work. Anyone can own, purchase, or inherit. For minors to purchase Nihonto, it is required that the guardians agree and sign on paper.