What changes to the piano did Johann Christian Bach make to the piano?

Answer 1

Actually it was not Johann Christian Bach who made the first changes, but his father, Johann Sebastian Bach.
Prior to Johann Sebastian Bach, the piano (or clavier as it was originally known) was not played using the thumbs or the fourth fingers. JS Bach was the first one to play the piano using his thumbs with his hands rounded on the keyboard. He hardly moved his hands, unlike keyboardists who preceded him, yet kept his fingers well rounded on the keyboard.

Johann Christian Bach was the eleventh son of Johann Sebastian Bach. He made some significant changes to the nature of piano music, as his compositional style tended towards the more expressive. He is less known, simply because the magnificent career of his father overshadowed his own work. Also, because Johann Christian spent much time in Britain, his style developed differently. He was sometimes known as the "English Bach".