Strong, curved left-hand fingers are essential for good cello technique and for developing a beautiful tone.  By curving your fingers and playing on the very tips of the fingers, you can stop the string completely, which in turn allows the string to vibrate fully when you play it. ​ Some of the cello exercises in Finger Exercises for the Cello, Book One were written specifically to help cellists develop well-curved fingers through double stops. 

When you get to Exercise No. 14 in Finger Exercises for the Cello, Book One, you can see that it is the first study in the book that specifically works on developing curved fingers. Here is an excerpt:

Although they are not beloved by my students, these exercises that focus on curved fingers have done SO much to help them build finger strength, play clearly, and play in tune!

Here is an excerpt from Exercise No. 20:​

I have also found that some students benefit from preparatory studies for these exercises. The preparatory studies have easier notes that allow you to focus on the finger and hand position.

Check out these free preparatory finger exercises that help you curve your fingers, stop the string completely, and get ready to play the essential cello double stop studies in Finger Exercises for the Cello, Book One.

Finger Exercise Preparatory Study No. 2

Finger Exercise Preparatory Study No. 4

Finger Exercise Preparatory Study No. 6