Fretboard Explorer — Mandolin

An interactive map of this reader's fretboard in GDAE: tap a note and it lights everywhere it occurs, so the 4 courses stop being 4 separate courses to memorise.

A number chart is unreadable at session speed until this map is automatic, because the chart names a degree and expects a position back inside one beat. Nobody gets that from a chord book; it comes from knowing where one pitch lives in three places.

A mandolin player reads a number and the two and the four — the chop lands on the backbeat whatever the digit is, so the chart tells this player where to put a chord, never when. The digit decides which four courses get stopped; the count-off already decided when, and no mark on the page argues with it.