White paper on crime 2010 Part2/Chapter6/Section3/1
As in the case of the extradition, after receiving a request from a foreign country to provide the evidence necessary to investigate a criminal case, Japan may provide assistance in accordance with the requirements and procedures provided in the Act on International Assistance in Investigation and Other Related Matters (Act No. 69 of 1980), under the guarantee of reciprocity, and through diplomatic channels, and even to foreign countries that are yet to have concluded treaties on assistance with Japan. In addition, this then enables Japan to receive the evidence necessary to undertake investigations from such foreign countries if their laws allow it.
Japan also concluded the Treaty between Japan and the United States of America on Mutual Legal Assistance in Criminal Matters (came into effect in 2006), the Treaty between Japan and the Republic of Korea on Mutual Legal Assistance in Criminal Matters (came into effect in 2007), the Treaty between Japan and the People's Republic of China on Mutual Legal Assistance in Criminal Matters (came into effect in 2008), and the Agreement between Japan and the Hong Kong Special Administrative Region of the People's Republic of China on Mutual Legal Assistance in Criminal Matters (came into effect in 2009). In addition, the Japanese Diet approved the Treaty between Japan and the Russian Federation on Mutual Legal Assistance in Criminal Matters and the Agreement between Japan and the European Union (EU) on Mutual Legal Assistance in Criminal Matters, with the arrangements currently being made toward their conclusion. These treaties or agreements on mutual legal assistance in criminal matters require both parties to provide mutual assistance, unless denial grounds exist, and to designate the “Central Authority” to send/receive requests for assistance (in Japan requests shall be sent by the Minister of Justice, the National Public Safety Commission, or persons designated by them, and received by the Minister of Justice or persons designated by the Minister) ensuring that requests are to be sent or received directly between the central authorities and not through diplomatic channels, and thereby making legal assistance in investigations more prompt and efficient.
Table 2-6-3-1 shows the number of requests for legal assistance in investigations made between Japan and foreign countries over the last 10 years. In Japan both the public prosecutors office and the police, etc. can request legal assistance in an investigation.