Some videos from some Karate Sensei showing practical applications of Kata techniques (Bunkai).
Sensei Nakayama illustrates bunkai from Tekki Nidan.
https://www.youtube.com/watch?v=ik2VPvwEZOo
Sensei Nakayama demonstrates bunkai from Tekki Sandan
https://www.youtube.com/watch?v=XR4I4kkbqdk