I wouldn't be surprised if a few Japanese people had Semitic blood in them because Jews and Muslims were great merchants who traveled all over the world. However, I would disagree with those people who think the Japanese culture was spawned by some lost tribe of Israel. Others have even tried to label the famous Song Dynasty Judge Bao Zheng a Jew because his home in Kaifeng has 6-pointed stars in the lattice work. It is simply a geometric design comprised of two triangles. Even a child doodling could accidentally draw this shape. Most importantly, Jews do not have the market cornered on the 6-pointed star. For instance, the
Yantra of the Hindu elephant god Ganesh uses the design:
The idea of Native Americans possibly being Jewish goes back to the 16th century. Biblical scholars of the time were trying to tie all of the world's different ethnic groups and cultures back to the Bible. The way they connected Native Americans was by suggesting that they were descended from one of the Lost Tribes of Israel:
"The first published attribution of a Lost Tribes origin for the Indians appeared in Joannes Federicus Luminus’s De extreme Dei iudicio et idorum vacatione (Antwerp: Antonium Tilenium Brechtanum, 1567). The conviction that the Amerindians were Jews of the Lost Tribes then spread quickly throughout the Western world, in time including among its proponents such men as John Dury, Thomas Thorowgood, John Eliot, Roger Williams, William Penn, and, later, an array of commentators on the Book of Mormon. There were also Pedro Simon and Antonio Vazques de Espinosa, who narrowed down the line of descent of the Amerindians to only one of the Lost Tribes—Issachar. The American Israelitism thesis was not, however, shared by all scholars. Hamon L’Estrange, for example, objected to it strongly, constructing as one argument against its legitimacy an Aristotelian syllogism of bemusing dimensions. Everyone knows, L’Estrange observed (in his Americans No Iewes [London:Henry Seile, 1652]), first, that Jews are forbidden to marry harlots and, second, that all Indian women are harlots. Whence it follows, he triumphantly declared, the Indians can under no circumstances be Jews."
You can read about it in this interesting paper:
Pollak, Michael. “The Revelation of a Jewish Presence in Seventeenth-Century China: Its Impact on Western Messianic Thought.” In
The Jews of China: Volume I – Historical and Comparative Perspectives, ed. Jonathan Goldstein and Frank Joseph Shulman, 50-70. Armonk, NY: M.E. Sharpe, 1999.