Today I got a DVD for next to nothing in a remainder shop, but a DVD with a difference. It was of a very good pianist (Zoltan Kocsis), playing some classical piano pieces.

One of the pieces was Beethoven's last piano sonata, Opus 111 in C minor. Maybe experts would find some faults with Kocsis' performance but I couldn't.

Watching him scorch his way through this amazing music made me realise that listening to CDs of piano music is a quite different experience from watching it being played as well.

When you watch a pianist at work, you know, a fraction of a second before it happens, what will then happen. When you see that right hand reaching out to the right and descending ferociously towards the keyboard, you know that what you are about to hear is going to be high, and loud. With a CD you have no clue as to what will hit you.

I believe that watching Kocsis' playing enhanced my enjoyment of it. It's almost as if your eyes are helping out with the listening. Your ears receive incoming data about what the music is doing, and so do your eyes.

This made me think of two other things. First, it made me remember a guy called Joseph Cooper, who used to appear on a classical music TV quiz show. One of his tricks was his "silent keyboard". He would play some piece on it, and all you could hear was a subdued clattering noise. What was the piece? Any real pianists watching this could always tell, and I often could too.

And the other thing this made me think that there is an opportunity here for a comic piano act, where the right hand descends with great ferocity onto the top end of the keyboard, and the comic pianist leans forward with enormous classical music type intensity toward the place of contact between his hand and the keyboard. But no loud high noise ensues, because Mr Comic Pianist pulls back from the loud noise at the last minute. Instead, his left hand, utterly unwatched by his intense classical music head, and hidden by his body as it leans forward with classical music intensity, plays a very low, very soft note. Maybe a Debussy type chord. The pianist turns in amazement to see what his left hand did. The point being that this is typically not what happens when you see a pianist play.

When you watch a conductor conducting an orchestra, you often know how loudly people are going to play, and who is going to play. But you don't know what they are going to play. You really don't know how it's going to sound. But with a pianist, you pretty much do know, just before it happens. As I say, this changes things. And it particularly changes things when the composer is late Beethoven, because with late Beethoven you never know what will come next. Unless, that is, you do.

I hadn't really taken all this in before. Well, it interested me.