Premise: Tsunetane Oda (小田常胤 , Oda Tsunetane , March 10, 1892 – February 11, 1955) was a judoka who was influential in the development of Kosen judo. His correct name was Join Oda, but through a misinterpretation of the kanji 常胤 he is more commonly known as Tsunetane.
Hypothesis: Kosen judo is a variant of judo created in the first half of the 20th century.