A valid visa or entry permit is usually required to stay in Hong Kong for 3 days. Even if you have permanent residence in Japan, this does not automatically give you the right to stay in Hong Kong. You need to check Hong Kong’s immigration policy to determine whether you can stay in Hong Kong for 3 days without a visa. If you do not meet the conditions, you may need to apply for a corresponding visa or temporary entry permit. It is recommended that you contact the Hong Kong Immigration Department or seek professional legal advice to obtain accurate information.