*I'm confused as to how I should play the second note below, B#. Does it mean it's a C? Is it possible? In which case, **why is it written like this, and not just C?**
*
In short, the B is raised a (1/2) step to B# as an adjustment to the Harmony of the song. To understand, let's harmonize the C# minor scale using triads.
As the key signature indicates, the key of C# minor has four sharps: (F#, C#, G# and D#).
Here are the first seven tones of the C# Natural Minor Scale:
C# - D# - E - F# - G# - A - B
and the Harmony:
i. C# Minor: C# - E - G#
ii. D# Diminished: D# - F# - A
III. E Major: E - G# - B
iv. F# Minor: F# - A - C#
v. G# Minor: G# - B - D#
VI. A Major: A - C# - E
VII. B Major: B - D# - F#
Notice that the chord on the fifth (Dominant) scale degree is Minor (G# Minor).
= = =
In Music Theory, the seventh scale tone (B Natural) of the diatonic (natural) minor scale is raised a half-step in order to get a major chord on the Dominant (fifth) scale degree. Here is the scale now:
C# - D# - E - F# - G# - A - B#
The Dominant Chord is now Major:
(V.) G# Major: G# - B# - D# or (5 - #7 - 2)
This (B#) also gives us a Leading Tone into the Octave and the Harmonic Minor Scale. By Leading Tone, I mean that the ascent into the Octave is now a 1/2 step (B# -> C# ) from the (previously) whole step (B natural -> C#). Also:
- NOTE: We now have a third pair of (1/2) steps in the scale
D# -> E (2 -> 3)
(5 -> 6) G# -> A
B# -> C# (7 -> 1)
Additionally, an Authentic Cadence (V/V7 -> I) as a resolution, in Minor, can sound very dramatic as chord tones resolve.
*IMPT: having a (B#) as the seventh degree of the scale creates these changes to the harmonized C# Minor Scale:
III+: E Augmented: E - G# - B#
V. G# Major: G# - B# - D#
vii. B# Diminished: B# -D# - F#
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