A barre chord device can include a strip of rubber, elastomeric or other resilient material with heat formed creases and protruding shims. A guitar player attaches the strip at discrete places to the index finger of his fretting hand. When the guitar musician performs a barre chord, the strip concentrates barre force to the strings. Shims press into the concave mid-finger keeping the strip straight on a string side to provide uniform barre pressure. Muscular effort is minimized. Creases cause the strip to fold neatly to a thumb side when the index finger is curled to perform non-barre chords and scales.