White paper on crime 2015 Part2/Chapter2
The Public Prosecutors Office consistsof the Supreme Public Prosecutors Office (headedbythe Prosecutor-General), eight High Public Prosecutors Offices (headed by a Superintending Prosecutor), 50 District Public Prosecutors Offices (headed by a Chief Prosecutor) with 203 branches, and 438 Local Public Prosecutors Offices. The different levels of publicprosecutors offices correspondto the respective level of thecourt.
In Japan, basically, public prosecutors hold the exclusive power to institute prosecution (either to try in public or to request for summary procedure). Public prosecutors decide not to prosecute where  the precondition for prosecution (e.g. victim's complaint for certain offenses) is not satisfied,  the act does not constitute an offense (or the suspect is notpunishable duetoinsanity, etc.), or  theevidence is not sufficient to provethe offense. Public prosecutors may also decide not to prosecute the case with sufficient evidence to prove the offense if they deem it unnecessary to prosecute based on factors such as the suspect's character, age, environment, gravity of the offense and circumstances after the offense (suspension of prosecution).