Bach played on clavichord.
When Bach was composing music, pianos didn’t exist. Instead, Bach composed almost all his music on a clavichord which, while sharing similarities with a piano, sounds completely different.
When you hear Bach played on a clavichord, it changes your entire perception of his music—makes you realize how it was meant to be heard.
Bach feels like he composed music for the person playing the instrument, as much as for the people listening to it.