1. The ventral surface of the first joint of the thumb touches the pen on the upper right.

2. The tip of the index finger is on the side of the middle finger, and the thumb contact is closer to the pen tip. The index finger and thumb should not be directly close to each other, but a little distance away;

3. The pen holder contacts the lower part of the middle finger nail, and the first joint line is on the upper side;

4. The penholder leans near the protruding position of the knuckles at the root of the index finger, not too far away.