One finger laid across a fret stops EVERY string it spans. A shape that wants an open string underneath the barre is not awkward, it is impossible.
It is the fact that makes barre chords difficult — a single finger has to hold six strings down evenly with the weakest part of its length — and it is also the fact that decides which shapes exist at all. Any chord voicing that relies on an open string sitting between two barred strings cannot be played, because the barre frets that string too and the chord becomes a different one.
Partial barres are real: many players barre only the top two or three strings, which changes the geometry entirely and makes some of those “impossible” shapes possible again. And a capo is a barre that never gets tired, which is exactly why it is used.
Estimate with the rule, then check it against the calculator that models it properly.
Open Guitar Chords →