Silent history of Japanese traditional mathematics. Who is Takahara Yoshitane? (Q2707048)

The present article contradicts in a quite original and convincing way the generally accepted idea of the spontaneous development of Japanese traditional mathematics (the wasan), at the end of the seventeenth century, out of the titanesque efforts of a mathematical genius, Seki Takakazu, the ``father'' of Japanese mathematics. By a careful examination of the political context of Japan during the period of seclusion and the policy of the Shogun with respect to European science, the author is able to show that despite the severe isolation of Japan and the absolute ban on Christian faith, European mathematical ideas were nonetheless secretly transmitted: in fact, the vector of transmission was the italian Jesuit Giuseppe Chiara who was given the Japanese name of Takahara Yoshitane and who taught European mathematics to Seki Takakazu and others. All this was made possible owing to the secret support of a high-ranking and leading official of the Shogunate named Ometsuke.