THE ALLOCATION OF INVESTIGATIVE AUTHORITY BETWEEN POLICE AND PROSECUTORS IS DISCUSSED, AND CONSTITUTIONAL SAFEGUARDS FOR THE SUBJECTS OF CRIMINAL INVESTIGATIONS ARE NOTED. THE PROCESSES OF INVESTIGATION AND ARREST ARE DESCRIBED, AS ARE PREREQUISITES FOR VARIOUS TYPES OF ARREST AND FOR PREPROSECUTION DETENTION. POST-ARREST PROCEEDINGS ARE OUTLINED, WITH REFERENCE TO A SUSPECT'S RIGHTS UPON DETENTION. LIMITATIONS ON THE MANNER IN WHICH SUSPECTS MAY BE INTERROGATED ARE NOTED. BASIC PRINCIPLES GOVERNING THE INSTITUTION OF PROSECUTION -- THAT PROSECUTION IS INITIATED BY THE STATE AND NOT BY PRIVATE INDIVIDUALS, AND THAT PROSECUTORS HOLD CONSIDERABLE DISCRETIONARY AUTHORITY -- ARE NOTED. FORMALITIES INCIDENT TO THE INSTITUTION OR PROSECUTION ARE DESCRIBED. IT IS POINTED OUT THAT, ALTHOUGH JAPANESE PROSECUTORS ARE GRANTED EXTENSIVE DISCRETIONARY POWERS, THE LAW PROVIDES FOR CHECKS ON THE EXERCISE OF THOSE POWERS. NOTES INCLUDE REFERENCES TO THE JAPANESE CODE OF CRIMINAL PROCEDURE. FOR PART 1, SEE NCJ-45328. (LKM)