In this book , we deal with the relationship between Japanese Buddhism and the theory of Karmic Retribution. This book consists of 2 chapters. In chapter 1 “Japanese gods and buddhas”, we discuss the problem of so-called “syncretization of Shintoism with Buddhism”. This syncretization doesn’t mean, however, the unification of these two established religions, but the double process in which a foreign religion Buddhism, on the one hand, has developed into Japanese Buddhism in contact with an ancient Japanese faith in native gods and the gods-faith has also been, on the other hand, formed into Shintoism in contact with Buddhism. Consequently Japanese Buddhism was supposed to have a unique feature. In chapter 2 “Japanese Buddhism”, we discuss this feature. We can summarize it in an idea that every living thing including humans has already realized itself by nature, in short, every living thing is born Buddha-natured. This idea is common to almost all the Japanese Buddhist sects. Many other ordinary Buddhists in the world, however, have firm faith of the traditional idea of karmic retribution. Our question is this: Are these two ideas compatible or not?