相关规则
Japan
Practice Relating to Rule 161. International Cooperation in Criminal Proceedings
Japan’s Law on Extradition (1953), as amended in 2004, states:
A fugitive shall not be surrendered in any of the following circumstances … [unless] the treaty of extradition provides otherwise:
(3) When the offence for which extradition is requested is not punishable by death, or by imprisonment for life or for a maximum term of three years or more by the laws, regulations or ordinances of the requesting country;
(4) When the act constituting the offence for which extradition is requested would not be punishable under the laws, regulations or ordinances of Japan by death or by imprisonment for life or for a maximum term of three years or more if the act were committed in Japan. 
Japan, Law on Extradition, 1953, as amended in 2004, Article 2.1(3) and (4).
Japan’s Law on Extradition (1953), as amended in 2004, states:
A fugitive shall not be surrendered in any of the following circumstances … [unless] the treaty of extradition provides otherwise:
(9) When the fugitive is a Japanese national. 
Japan, Law on Extradition, 1953, as amended in 2004, Article 2.1(9).
Japan’s Law on Extradition (1953), as amended in 2004, states:
A fugitive shall not be surrendered in any of the following circumstances …:
(1) When the offence for which extradition is requested is a political offence;
(2) When the request for extradition is deemed to have been made with a view to trying or punishing the fugitive for a political offence which he has committed. 
Japan, Law on Extradition, 1953, as amended in 2004, Article 2.1(1) and (2).