Aikido is sometimes thought to lack choking techniques, but this is not the case. Nishio Sensei taught a number of different shimewaza. Also, the use of gyakuwaza (techniques the oppose normal joint movement) are perfectly admissable provided they are done in a way to avoid injuring our opponent.
Philip Greenwood
Uke: Heather Greenwood, Dan Cole, Mike Kindsvater, Judah Cole
http://greenwoodaikido.com/
https://nishikazeaikido.org/
http://nishikazeaikido.tv
