Which hand position you should use for tearing a deck of cards?
The hand position will primarily depend on which style you use to tear a deck of cards. The one where you place the deck of cards vertically, like in the picture below, used to be the most popular style.
You’d want to grab the deck really tight, aim for a flat line between your fingers and tear the deck with a twisting motion while keeping the deck together. Truth to be told I don’t really practice this style so you may want to get additional details from someone who does.
The second style is how I do it and I learned it from Dennis Rogers. Hold the deck with your grasping hand, like shown below, and hold it tight.
Use your other hand for a pinch grip and place the deck between your thumb and the side of the index finger. Wrap other fingers as much as you can underneath and tear the deck. If done correctly, it should be a straight tear right through the middle of the deck. Just push down with your grasping hand and pull up with the other one.