If you play guitar or any other fretted instrument, Fretspace helps you to unlock the fretboard and find new ways to play chords and scales and see how they are related to each other. Fretspace is a chord and scale editor for guitars and other fretted instruments - banjos, mandolins, ukuleles etc. It can be used to create charts of chords and scales in any tuning. Chord and scale shapes are displayed in standard grid boxes, and notes can be added or removed by clicking. There are also chord and scale pickers that calculate and display almost any possible chord and scale shape for the current tuning. Fretspace automatically identifies and labels chords and scales, and automatically calculates fingerings (both are editable). There are options for labelling notes and for displaying root notes in a different colour. A tunings editor allows custom tunings to be created, in addition to the range of standard and alternative tunings that are provided. A Play button allows chords and scales to be played using MIDI playback. Fretspace contains a number of tools for moving shapes around the fretboard or creating inversions. Charts can be printed, and shapes can also be copied and pasted into other applications as PDF graphics. The program includes a step-by-step tutorial and detailed reference manual, which are available from the Help menu (and can be printed or viewed on screen). There is also an online series of Fretspace Explorations articles, which show how you can use Fretspace to explore music with a guitar or other fretted instrument. Fretspace runs on macOS 10.11 (El Capitan) or later.