As fans of old delta blues will already know, even two or three strings on a guitar can be too many when belting out soulful music on a guitar-like instrument. Rather than changing the pitch of a long piece of tuned wire with a glass bottle or steel blade though, the FretPen uses technology to offer players three full octaves from just three frets on a real wood neck and a companion iPhone app. Oh, and it's also a pen.
The FretPen one-stringed guitar and pen
The maple fretboard of the FretPen has the same number of steel frets as the travel-friendly PocketStrings chord shape practice aid that caught our eye at 2012's Winter NAMM, but not nearly as many strings. In fact, the guitar-shaped FretPen only has one short string running between its teeny tuning head and base block.