Ben Johnston created a system of notation for pieces in just intonation where the unmarked C, F, and G major chords are just major chords (4:5:6) and accidentals create just tuning in other keys. Between 2000 and 2003, Wolfgang von Schweinitz and Marc Sabat developed the Extended Helmholtz-Ellis Just Intonation (JI) pitch notation, a modern adaptation and extension of the notation principles first used by Hermann von Helmholtz, Arthur von Oettingen, and Alexander John Ellis that some other musicians use for notating extended just intonation.