I would like to ask a question about the speed of playing a piece on the piano.

For example, I have listened to a special “Polonaise” in G-minor
from the Maria Magdalena Notebook by Johann Sebastian Bach many years ago,
and it was played on a violin very slowly, in fact,
it was very touching and the violin was almost “weeping”.

I then re-discovered the same Polonaise a few years ago on a CD called “Visions of Bach”.
And here again it is played on the violin (Celtic Fiddle) very slowly, thoughtfully and very sensitively.

I also heard it played on a piano and it was played rather fast.
Does anyone know how to play these pieces, are there any rules
or is it everyone’s own choice how to express themselves?

I have also noticed Sonatas of D. Scarlatti often being played very quickly
and only rarely does anyone play Scarlatti slowly enough to appreciate every single tone
and "let it linger a little".

Are there any rules how to play or is it everyone's own choice?

Kristinaolga,
To put it simply and in your own words, there are no rules and it's everyone's choice. Tempos, even when indicated by words (or metronomic values), are subjective and part of what makes music a human-only experience. Certainly there are choices that communicate agreeably to more people than others. I love the fact that many (if not most) of JS Bach's solo keyboard works do not have a tempo indication. This means that each interpretor must find what is the proper tempo for themself given their understanding of the elements and spirit of the work and it's composer. Further, speed/velocity is one thing but tempo is another. The first is scientific and the second is psychological (the same as frequency to pitch). People appreciate a tempo individually; what seems right to one may seem rushed or lacking to another. Therefore within the bounds of your good taste and understanding, you need to satisfy yourself first and foremost; there will always be others who both agree and disagree with your idea but you are -at that moment- the interpretor. Good luck as you seek to find the spirit of the work behind the page of music.

Regards

Thank you, musical-md, that is a great answer !

I like what you mention about “good taste”. That explains everything.

Thanks again from Kristinaolga.

As far as I am concerned, the rule is 'Don't be a nut about speed'. No reason why you should play everything as fast as possible, just as you can.
But it does depend on the piece, and how you want to present it, of course.

Let me add another thought. IMO, the task of finding the right tempo is equal to the task of identifiying the chief thematic element(s). Once that is identified, then a "proper" tempo can be found within reason. The problem is that too many casual players don't identify the right thematic element of a work. The supreme (most common) example of this is the 1st movement of the Beethoven "Moonlight" Sonata. Even if we dispense with the observation of the tempo indication and cut-time-signature, we are still left with an ostinato of triplet broken chords, an infrequent change of harmony, against which a melody finally appears and is expressed casually. The tempo of this work should not be governed by the triplets, but by the melody. To use exageration as a means of discovery, imagine that we play the triplets so slowly that we play a note every five seconds! There would be no ability to comprehend the structure (not to mention even appreciate the melody) whatsoever. It would be akin to standing with your nose on a large billboard, having no ability to see the picture at all. On the other hand, a ridiculously fast tempo would result in a loss of the duple meter which would be absorbed into frantic passages where four bars go by without appreciating any detail except the very largest. It might sound like your were playing a Schenker reductional analysis (or were now viewing that billboard from too far a distance to see any but the largest shapes). Finding what's the important feature and displaying it correctly goes a long way.

Thank you for your kind explanations, techneut and musical-md,

it is very much appreciated.

Thanks again from Kristinaolga.

Piano tone is solely determined by the speed that the hammer travels to the strings. As said by the others, it will depend on the piece you are playing and on what tempo you want it to be played.