What lessons can be learned from the Japanese experience with its main bank system and, more broadly, its financial system? Mow relevant is that experience for the developing market economies? For the transforming socialist economies? These are the central themes of this chapter, which explores a range of key generic issues in the design of good financial systems for developing market and transforming socialist economies in light of Japanese experience. Consonant with the objectives of this book, a major focus is on the main bank system in its heyday, namely the rapid growth era from the early 1950s to the early 1970s; and on placing the main bank system within the overall architecture of the Japanese financial system, its structure and the government's financial policies