A# Major — Dobro
The shapes, and where A# Major falls when the circle calls a key.
A# Major spells A# – D – F. In a jam nobody says that out loud — they call a key and a number, and this chord is the vii° of B. Learning it that way is what lets you play a tune you have never heard.
The dobro chair owns the answering voice. Face-up in open G, a chord here is not a shape to grab but a fret to lay the bar across, or a short slant of it, and the slide into that fret is half the sound — which is why the seat waits for a hole in the vocal rather than filling every bar.
Every position below is the bar on the GBDGBD strings — straight across a fret, or tilted into a short slant — with the open strings first and the bar moving up the neck after them, and a quality open G cannot spell that way is marked rather than drawn as a grip no steel can hold.