The triangle choke as used in Judo and Brazilian Jiu-jitsu has its origins in early 20th century Judo:
This technique was first introduced by the students of the Rokuko Judo Club at the Kosen Judo [tournament] in 1911...
This technique was developed by two people, the late Judo teacher at Rokutaka Okayama, Yaichibei Kanemitsu 9th-dan (Kitō-ryū) and the player at the school, Masaru Hayakawa (later 8th-dan), and Oyama at the school. The improvements were made by Shozo and completed.
- 乱取外編・三角絞め (bokuden.or.jp/~bunbkan)
However, most grappling techniques have much older origins (e.g. takedowns, joint-locks, rear naked chokes) in earlier forms of martial art, and many have developed parallelly in different arts.
Are there any records of triangle chokes being used prior to its introduction to Judo? E.g. in ko-ryu jujutsu, HEMA, etc.