One of the questions that comes up every now and then in the Israeli-Japanese discourse is whether the Japanese are descendents of the Israelite Lost Tribes.
Brief history: After the Israelite kingdom was run over by the Assyrians in the 8th century B.C.E, ten of the Israelite tribes were exiled and never heard of again. Today's Jews are descendents of the kingdom of Yehudah, specifically three tribes: Yehudah, Binyamin and Levi. Over the centuries, many theories have been put forward as to the whereabouts of the Ten Lost Tribes. In recent years, a group of Indians came forward and claimed they are descendents of the tribe of Menasheh; several of them made aliyah to Israel.
One of the theories is that the Ten Tribes (or some of them) ended up in Japan. Proponents of this theory point to Shinto, the native religion of Japan, purportedly showing that several traditions in Shinto can be traced back to biblical Jewish practices. The movie below summarises some of these finding, while this website is more comprehensive.
Personally, this all sounds a bit far-fetched, but who knows? After all, it has been almost 3,000 years so anything is possible. To me, the most frightening thought in this whole discussion is: imagine a world with 140 million Jews! The mere thought has me covered in cold sweat.