Introduction At the end of the last chapter, the question was posed as to whether the genetic relationship between the Bulu ecotype from Java and the ‘ordinary Japanese rice’ ecotype was just due to trade, or whether it was actually due to immigrants bringing their rice to Japan. This chapter and the following one will answer that question. This necessitates reviewing a lot of scientific and technical material, some of it open to more than one interpretation. I have given quite a full account of the data for readers who want to evaluate it for themselves, but have also summarized the results of the investigation briefly and in non-technical language at the end of the chapters for other readers.