This document discusses the implementation of a Diagnosis-Procedure-Combination (DPC) classification system for hospitals in Japan as an alternative to traditional fee-for-service reimbursement. It provides background on Japan's healthcare system and reimbursement structure. It then outlines several feasibility studies conducted in the late 1990s to evaluate different case-based payment models like the US DRG system. This led to the introduction of a DPC-based per diem payment system for participating hospitals in 2003, with the goal of reducing costs. Over time the DPC system was expanded and saw increased adoption among hospitals in Japan.