According to A. Cortot thumb passage is a crucial element in the development of the piano technique which cannot be overestimated. In his work "Rational principles of piano technique" we read: “We think that we are not mistaken in looking upon the universally admitted use of passing the thumb, that eminent factor of velocity, father of octaviations, as the essential technical principle in the veritable revolution”.
The author suggests a series of exercises that help the student to acquire agility and nimbleness. In this context it can be indicated that the passage of thumb is fundamental in the study of scales and arpeggios.
In this exercise, taken from his book, you must hold down a key so you always have a point of reference and at the same time avoid unnecessary movements of hand.
1 The exercise should be done by both the right and the left hand, the fingering being exactly the same.
Braille Example (the example is written for the right hand, but the exercise can also be applied to the left hand with the same fingering)
2 The exercise is similar to the previous one, except that two keys are to be held down.
Right Hand
Braille Example
Left hand
Braille Example
The fingering in exercise 3 is the same for the right hand and for the left hand.
Braille Example