16. Allegro tenebroso

This prelude requires considerable technique, but it is also a prelude that is performed at a wide variety of different tempos. The indication is Allegro tenebroso. The word "tenebroso" might not be very familiar, might it? It primarily means eerie, dark, and mysterious. In short, it essentially evokes a sense of the supernatural and monstrous. If one considers only "tenebroso," this prelude sounds mysterious even when played slowly. However, since it is still an allegro, a certain tempo is desirable. Horowitz's recording is probably the fastest in this century. Please listen to it once. Conversely, there are countless examples of slower tempos.

While there's no need to play it exceptionally fast like Horowitz, it's good to listen to it as one idea. Furthermore, in this prelude, intense, almost percussive bass notes are repeated, which alone can create an enormous volume. This can make the crucial melodic line difficult to hear, often resulting in a performance that is unclear and muddled.

In passages with many low notes, maintain balance even at forte, and play the notes that should be heard clearly.

Fundamentally, this prelude is composed of two thematic materials. These two materials appear almost alternately.

• The first material is the melodic line in measures 3-6.
• The second material is the bass melody in measures 7-8.

These materials appear alternately, constantly changing their form. Keeping this in mind, for example, in measure 22, sixteenth notes appear in the right hand. One might be tempted to emphasize these, but looking at the left hand reveals it to be the second material, so that should be emphasized instead. In measure 27, triplets appear in the right hand, but these are merely a variation of the first material.

For musical interpretation, play it so mysteriously that it evokes a sense of fear in the listeners, and from the sotto voce in measure 42 towards the final measure, gradually increase the tension. In particular, the last two measures are crucial for dynamics. Conclude with the greatest possible crescendo and forte. Naturally, ritardando and similar effects are forbidden.