TSDTexan
Master of Arts
1.
That to me is a knifehand - the 'tool' is the side of your open hand, from little finger (pinky?) to wrist.
2.
A reverse knifehand is from index finger to wrist with you thumb tucked out of the way (is that ridge hand to others?)
3.
"Straight fingertip" is what I think of when you say "spearhand" - mechanics like a 'normal' punch, but using the fingertips?
in karate number one is a Shuto Uchi, knifehand strike or Sonnal Chigi or Sudo in Korean. can be palm up..
or
palm down.
number two is a Haito Uchi, or ridge hand or in korean Sonnaldeung Bakkat Chigi or Yeogsudo
number three is a Nukite Uchi spearhand or Gwansu