Regarding Bach's A minor, as stated in the preceding Prelude No. 20 from Book I of the Well-Tempered Clavier, a slow tempo in A minor expresses darkness, sadness, and so forth, while a fast tempo expresses joy. However, since Bach's works lack tempo markings or specific tempo indications, there are pieces, like this fugue, that can be interpreted as either slow or fast.

For instance, when faced with such a choice, how should one make a decision? One method is to draw upon years of experience and refer to numerous works, or one can exercise a certain degree of imagination, thinking, "Given the way this piece is written, the tempo is likely fast." Furthermore, criteria for judgment include considerations such as "a slow tempo where trills become too close to the main note is undesirable."

So, in the case of this fugue, how should the tempo be determined? First, the characteristics of this fugue are as follows:

• It is a long piece: a colossal fugue spanning 87 measures, and it is in four voices.
• The theme is long: The theme extends for four measures, beginning in measure 1 and ending on the first note, A, of measure 4.

These two reasons alone suggest that playing this fugue at a fast tempo makes the piece clearer and helps maintain tension. In the author's personal opinion, playing this fugue at a relatively fast tempo, incorporating a certain sense of joy, makes the piece more cohesive and easier to listen to.