B7-9 (B7b9) altered chord
Altered B chord for piano presented by keyboard diagrams.
Explanation: The B7-9 alter the B9 by the change of one note. The chord name can also be written as B7b9 or B7(b9).
Theory: The B7-9 are identical with the B9 except that the major ninth is flattenedThe tone is one half step lower.
Notes: B - D# - F# - A - C