Abstract: A single instrument can be played as a guitar or a banjo with a simple adjustment. It has six guitar strings (1 to 6), plus a seventh, shorter string (7). Its neck (12) is widened for part (12W) of its length, starting from the body (10) and then narrows. The six strings run over the pickups (28 and 30) and tuning bridge (24) and are anchored on the backside. Their opposite ends are wound around the tuning pegs at the end of the neck. A shift lever (38S) is attached to the first peg for rapidly changing the tuning from its normal pitch, E, down to D. The seventh string is tuned to G, as with the fifth string of a banjo. Its ball or stopped end is captivated by a knurled adjustment nut (42) under the body. It passes through the body and over the bridge (24), the pickups (28 and 30), over the body and widened part of the neck. Its free end is anchored at an anchor hole (12H) in the neck. To play the instrument as a guitar, the player uses the first six strings, which are tuned to the guitar pitches, i.e.