B

Sahasrara, the Crown chakra, is described in the classical Sanskrit sources through its own extensive symbolism, most famously as a thousand petalled lotus, with no reference to Western musical pitch. Its pairing with the note B in the modern chakra-tone system completes the ascending mapping used throughout these entries, the seventh and final scale degree matched to the seventh and topmost chakra, a construction of twentieth century Theosophical and later New Age writing rather than an element of the older tradition.

B's position as the seventh degree of the C major scale, the leading tone that sits a single semitone below the octave and creates a strong pull of resolution back up to C, is sometimes read by contemporary esoteric writers as fitting for a chakra associated with transcendence and completion, the note itself seeming to reach upward toward the octave the way Sahasrara is described as opening toward states beyond the embodied self; this is, again, an interpretive reading added after the correspondence was already fixed rather than the reasoning behind its original construction.

Sources The Serpent PowerSir John Woodroffe (Arthur Avalon) with Rainbow Body: A History of the Western Chakra System from Blavatsky to BrennanKurt Leland

B is the seventh degree of the C major scale, called Ti (or Si in some traditions) in movable-doh solfège, and functions in tonal harmony as the leading tone, the pitch sitting a single semitone below the tonic whose strong pull toward resolution upward into the octave is one of the basic engines driving harmonic motion in Western tonal music. This half-step relationship between the seventh degree and the octave is a defining structural feature of the major scale itself, distinguishing it from scales built with a whole step in that position.

B major and B minor sit at a considerable distance from C major on the circle of fifths, the theoretical device mapping key relationships by ascending fifths, which is one reason modulations between C and B feel comparatively dramatic in tonal composition; the same acoustic fact, that resolving a leading tone upward by a single semitone produces a strong sense of arrival, is exploited constantly across genres from classical cadences to popular music's use of a raised seventh to signal an imminent return to the tonic chord.