Toho 吐方（emetic remedy）is one of the three distinctive techniques in traditional Chinese/Japanese medicine. In the Edo era 江戸時代 in Japan, it is alleged that Okumura Ryochiku 奥村良筑（1689–1761）was the pioneer of this medical technique, and after him, his disciples Nagatomi Dokushoan 永富独嘯庵（1732–1766）, Ogino Daishu 荻野台州（1737–1806）, and Tanaka Hitsudai 田中必大（1725–1801）succeeded him both in practice and theoretical formulations. At the same time, Emi Sanpaku 恵美三白（1707–1781）implemented it in his own method. However, it was an extremely difficult technique for the followers to emulate. Therefore, we cannot find any further practitioners in his school. Then, Nakagami Kinkei 中神琴渓（1744–1833）integrating the attainments above, establishing this method as one of his repertoire of treatments. Though his achievement was also enormously challenging for his apprentices to follow, they efficaciously succeeded even in a part of it, as he taught them diligently. Kako Kakushu 加古角洲（1776–1832）was one who practiced it, and Kitamura Ryotaku 喜多村 良宅（18C-19C）was another who predominantly used it in the treatment of psychiatry. Finally, Watanabe Kunʼyo 渡邉君耀（19C）described those phases almost at the end of the Edo era in one short work. We should learn the philosophy but just clever techniques from them for our medicine today.
