Hajiki (pull-off)
Hajiki is the technique where you sound the string by pulling it far enough so it snaps out of your finger, causing it to sound.
If you are sounding the '0' position, pull the string with your index finger towards your palm until it snaps out.
If you are sounding '3', press down the 3rd position with the index finger, and pull the string towards your palm with the ring finger.
Hajiki may a difficult technique to understand. Once again, just imitate what's being shown on the video, and you will be doing it right.