Under Article 203(1),204(1) and 205(1) of the Code of Criminal Procedure, a suspect who is arrested might be placed under physical restraint for a maximum of 72 hours.

　　　　　If a public prosecutor believes that it is not necessary to detain the suspect, he or she will release the suspect. If a public prosecutor believes that it is necessary to detain the suspect, he or she will request a judge to detain the suspect.

　　　　　In general, the suspect might be detained for a maximum of 20 days under Article 208(1) and (2) of the Code of Civil Procedure.

　　　　　Thus, there is a possibility that a suspect will be physically

detained for a maximum of 23 days (2o days and 72 hours) after being arrested.

Please refer to the articles of Japanese law translation.

Artice 203(1) When a judicial police officer has arrested a suspect upon an arrest warrant or has received a suspect who was arrested upon an arrest warrant, he/she shall immediately inform the suspect of the essential facts of the suspected crime and the fact that the suspect may appoint defense counsel and then, giving the suspect an opportunity for explanation, he/she shall immediately release the suspect when he/she believes that it is not necessary to detain the suspect, or shall carry out the procedure of referring the suspect together with the documents and articles of evidence to a public prosecutor within 48 hours of the suspect being placed under physical restraint when he/she believes that it is necessary to detain the suspect. 

Article 204(1) When a public prosecutor has arrested a suspect upon an arrest warrant or has received a suspect who was arrested upon an arrest warrant (excluding such suspect as is referred in accordance with the preceding Article), he/she shall immediately inform the suspect of the essential facts of the suspected crime and the fact that the suspect may appoint defense counsel and then, giving the suspect an opportunity for explanation, he/she shall immediately release the suspect when he/she believes that it is not necessary to detain the suspect, or shall request a judge to detain the suspect within 48 hours of the suspect being placed under physical restraint when he/she believes that it is necessary to detain the suspect; provided, however, that when the public prosecutor has instituted prosecution during the time limitation, he/she shall not be required to request detention.

Article 205(1) When a public prosecutor has received a suspect referred pursuant to the provision of Article 203, he/she shall give the suspect an opportunity for explanation and shall immediately release the suspect when he/she believes that it is not necessary to detain the suspect, or shall request a judge to detain the suspect within 24 hours of receiving the suspect when he/she believes that it is necessary to detain the suspect.

Article 208 (1)When a public prosecutor has not instituted prosecution against a suspect regarding a case in which the suspect was detained pursuant to the provisions of the preceding Article within ten days of the request for detention, he/she shall immediately release the suspect.

 (2)When a judge deems unavoidable circumstances exist, he/she may extend the period set forth in the preceding paragraph upon the request of a public prosecutor. The total period of such extensions shall not exceed ten days.