Bb Ionian

The Bb Ionian mode (also written A#) — Bb C D Eb F G A — shown across the guitar neck.

Also written A# Ionian. A# and Bb are the same pitch, though spelling it from A# would need double accidentals (A# B# C## D# E# F## G##), which is why Bb is the name in use.

Swipe the neck sideways to see the higher frets.

Bb Ionian is the major scale — same seven notes, same order. The mode name describes which chord you treat as home, not a different set of notes.

The tool shows this from its parent key, Bb major, with Bb marked as where Ionian begins, the same seven notes centered on Bb.