While this may be due to the author's limited knowledge, the key of B major (H-dur) in Bach's works could not be found outside of the first and second books of The Well-Tempered Clavier. Although B major might exist in other works, at least in Bach's oeuvre, B major appears to be an extremely rare key.

The characteristics of this key can be described as extremely optimistic, peaceful, and understated. Although this prelude is fundamentally written in three voices, from beginning to end, sixteenth notes are present in one of the voices, and it can be considered a piece that progresses steadily without pausing its cadential motion. It does not stop or linger unnecessarily. Furthermore, as it is not a busy key, please proceed at a comfortable tempo.

From measure 16 onwards, it becomes four voices, but until then, it is strictly written in three voices, so independence of voices is desired. It is desirable to give each voice—soprano, alto, and bass—a distinct timbre, allowing them to be heard as separate lines.

Midway, for about 7-8 measures, the tension slightly increases, but please consider it fundamentally a calm piece. Even after measure 16, when it becomes four voices, it does not become dramatic; rather, consider it as merely adding a bit of thickness to the texture, and conclude peacefully.