Yoshida Mitsuyoshi

Yoshida Mitsuyoshi (Japanese吉田 光 由; * 1598, † 1672), and Yoshida Koyu ( the Sino- Japanese reading of his name ), was a Japanese mathematician in the Edo period. He authored the widely used arithmetic book Jinkōki (尘 劫 记), won the major influence on both subsequent authors as well as on the teaching of mathematics.

Life

Yoshida was the son of a doctor and came from Saga, a suburb of Kyoto. His relationship to the rich merchant family Suminokura allowed him extensive training and gave the mathematically talented Yoshida access to Chinese mathematics books such as the 1592 published SANPO Toso (Chinese算法 统 宗pinyin Suànfă tŏngzóng ) to which it should fall back later in his own work.

The economic boom after the end of the political turmoil of the Azuchi - Momoyama period and the unification of the country under the Tokugawa shogunate was accompanied by an increased need for mathematical calculations, which were hampered by imperfect process and a complicated monetary system. Permanent conversions between the gold standard of Edo, Kyoto and Osaka, the silver currency and various copper currencies and between the various weights and measures were required. As an aid in such calculations, it was the Japanese abacus, called the Soroban, more important. Introductions in its use and in the main calculation methods, however, were still in short supply.

This gap was trying Yoshida - as a century before European Reckoner as Adam Ries - 1627 with his arithmetic book Jinkōki to close. Next required daily mathematical methods It also contained numerous tasks with Puzzle character for which Yoshida fell back partly on Chinese models such as the SANPO Toso. He revised his work until the end of 1641 several times and tried through innovations such as colored illustrations, different colors for positive numbers (red) and negative numbers (black) and finally the " still problems to be solved ," a collection of twelve unresolved tasks, its obvious outdo numerous imitators.

After 1641 to Yoshida river turned to construction projects, it is disputed whether he actually wrote a book attributed to him of 1643. Relatively safe, he was involved in two calendar works, the Wakan hens Gōunzen of 1645 and the Koreki Binran of 1648th Yoshida Mitsuyoshi died 1672.

Work

Yoshida's most famous work, the Jinkōki, appeared 1627-1641 in at least six partly quite different issues. It has been used up to the Europe-oriented education reforms at the beginning of the Meiji period, among others, in the Terakoya schools. The Jinkōki belongs to breitenwirksamsten range of traditional Japanese mathematics (和 算, Wasan ), which was in contrast to the more scientifically oriented mathematics experts about the Seki school thought (after Seki Takakazu ) and the cultic significance Sangaku panels for home use. For practical use of the work contributed to the numerous drawings contained therein, probably designed by the author. A mathematical notation in the modern sense, he renounced all tasks are described in words and in respect of the calculation using the Soroban.

The currently known issues of Jinkōki in detail:

Yoshida's book was only one of many arithmetic books that emerged in the first half of the 17th century in Japan. However, it won the apparently large influence on both subsequent authors who studied his author by his own admission as an imitator and black copiers, as well as on the teaching of mathematics. A hundred years after Yoshida's death hardly appeared a book without " problems to be solved ," whose number was sometimes up to 200. By 1913, more than 300 computer books were published, bearing the term Jinkōki behalf. Only with the education reforms of the Meiji period from 1872, and the related preference Western Mathematics ( Yosan ) lost Yoshida important. He has been since the late 1990s, known again by new editions of his work in English and modern Japanese language.

Expenditure

• Osamu Takenouchi et al: Jinkōki. Wasan Institute, Tokyo 2000 ( English edition contains the June 1641 edition of parts of November 1641 as a facsimile and English translation extensive notes and explanations Japanese edition ISBN 4876391203 ).