The term "open chords" refers to chord shapes which contain at least one open string. There are occasional exceptions in this book, but all chord shapes shown under an open chords heading will occur in the first four frets. Where there is more than one option for a particular chord, the easiest version is boxed.
Throughout the book, chord shapes are given from all twelve possible root notes used in music. It is recommended that you learn each shape and then transpose it to all the other keys. This will result in you being able to play any chord anywhere on the fretboard.