The Judo version of the triangle choke (Sankaku Jime) is a move that we rarely see in BJJ. BJJ champion Rafael Mendes likes to use these following setups whic can be very useful in BJJ where your opponents will not see the danger coming from some seemingly neutral positions.
Matt D’Aquino is a 3rd Degree Judo Black belt, 2008 Beijing Olympian and an Australian submission Grappling champion. He is also a BJJ purple belt.
In these videos, he shows you how Rafa does it from all difrent angles.
First check out Rafa using the reverse triangle from side control at 3:24 and from a sprawl position at 4:50 against Bill Cooper:
Now Mat D’Aquino shows various setups:
From the Kimura:
https://www.youtube.com/watch?v=GmzS3pcfaPU
https://www.youtube.com/watch?v=4DmqXdUPP5s
https://www.youtube.com/watch?v=jakKzlXg180