Non-Japanese people can succeed to Japanese inherited properties if they are legal heirs.

Summary of legal heir

• The Japanese spouse can be the legal heir
• The Japanese children also can be legal heirs
• The Japanese parents can be the legal heir if the Japanese didn't have children
• The Japanese siblings can be the legal heir if the Japanese didn't have children and parents

How to make sure relation with the Japanese inheritee

• Basically you should make sure the family tree of Japanese by family register
• You need to vital record of your country if the Japanese had been living and dead in your country.