Harmonix has explained how the Rock Band 3 guitar peripheral works.
An in-game trainer teaches you chord shapes and numbering on screen while the playing along to songs.
Any chords which aren’t relevant to the song are blanked out, making it easy for you to understand which strings you should be using.
Harmonix explained that you can’t actually play harmonic notes with the guitar, as the game has to read what you are doing with your left hand; the only way it can do this is by you pushing the strings down with the fret.
Watch and learn through the video below.
Rock Band 3’s out later this year.