Harmony is a difficult and complex part of music theory with chord spelling and construction at its very basis. What is a chord? Is it C - E - G# or C - E - Ab? You like the sound of those four notes on your guitar, but is it a chord? And if so, what is it called? These are typical issues facing the creative musician when trying to bring a new song to paper. Music theory is often complex and correctly spelling a chord that may have sharps and flats, double flats or double sharps is not always easy. This is where the traditional chord books and apps become useless and ChordLab steps in.