There is no chord dictionary in this page. A chord is a set of note names — C major is C, E and G — and a fretboard is six strings whose pitch you know. So the shapes are found by searching: for every position on the neck, which combinations of frets sound only those notes, put the root in the bass, and can be reached by one hand?
A generator that knows no guitar tradition should rediscover the shapes every guitarist already plays. Given only pitch classes and hand geometry, it produces x32010 for C, 320003 for G, xx0232 for D and 022100 for E — fifteen of fifteen standard open and barre shapes, each ranked first.
It did not, at first. It preferred 103211 to the F barre chord because that shape needs one finger fewer and leaves the A string open. But a finger laid across the first fret presses every string it spans, so that open A cannot exist under a barre — the shape it was scoring is unplayable. Modelling the barre as a physical object rather than as a discount on the finger count fixed the last one.
The ukulele caught a second assumption. "Skipping the bottom strings is free" is true of a guitar and false of a soprano ukulele, whose G string is its second highest — so the search offered x000 for A minor, which no player has ever used, instead of 2000. Stated properly — a muted string is free only when it sits below everything you are playing — the ukulele produces 0003, 0232 and 2220 for C, G and D, and the guitar is untouched. A rule that fixes one instrument without disturbing the other is usually the real rule.
Because the easiest shape is rarely the right one. A chord played at the fifth fret has a different weight to the same chord at the nut, the fingering that follows from the chord before it saves a scramble, and some voicings leave a finger free for a melody note. The list is ordered by how easy the shape is, not by how good it sounds.
A capo raises every open string by the number of frets it sits at, which is the same as playing a different instrument. Set one and the shapes are recomputed against that instrument, with the fret numbers counted from the capo — so the shape shown is the shape your hand makes. That is why a guitarist with a capo at 3 plays a "D shape" and everyone hears an F.
Because the strings are different notes, so every shape that produced those pitches has moved. Nothing was rewritten for DADGAD — the search simply ran against a different set of six numbers, which is the whole reason for generating shapes rather than storing them.
It separates the strings in time, up to a full second apart. At that speed you can hear each note arrive and place it against the diagram, which is how you learn to tell whether a chord is ringing properly or whether one string is buzzing, muted by a finger, or out of tune. At the other end of the slider everything sounds at once, which is a chord rather than a strum.
No. Each string is a Karplus–Strong pluck — a burst of noise fed round a delay line the length of one period, which is a startlingly good imitation of a plucked string for four lines of code, and audibly not a recording. It is there to let you check which notes you have, not to sound pretty.
No change to this page at all since the earliest archived release (v4.65). The full history for the site is in the changelog.