Open G changes the note layout across the guitar neck. Start with the string notes, choose a scale that fits the musical key, then use the fretboard and tab together so the pattern connects to actual notes instead of a shape learned by rote.
Open G string notes
Open G is commonly tuned from the lowest string to the highest as D-G-D-G-B-D. The same notes read from the highest string down are D-B-G-D-G-D, which is the order used in the scale finder. The open strings contain the notes G, B and D - the root, third and fifth of a G major chord.
Those open strings do not contain every note in the G major scale. A, C, E and F-sharp are fretted notes. A scale map shows where all seven notes fall, including notes that are not available as open strings.
Choose a key and scale before choosing a pattern
A tuning changes where notes sit on the fretboard; it does not choose the scale for you. For a G major sound, select G as the key, Major as the scale and Open G as the tuning. The resulting map shows G, A, B, C, D, E and F-sharp across all six strings.
Try the G major scale in Open G to compare the note map with the five tab positions. For a bluesier sound, open the G blues scale in Open G and compare which notes change.
Play one octave on the fifth string
Use the lower G string, which is the fifth string when counting from the thinnest string. Play frets 0, 2, 4, 5, 7, 9, 11 and 12. These give G, A, B, C, D, E, F-sharp and G in ascending order. Fret 0 means play the open string.
Play the sequence slowly, say each note name, then come back down in reverse. This is a one-string exercise, so move your hand along the neck as needed. It is different from the scale finder's five-fret position fragments, which spread the notes across strings.
Once that octave sounds familiar, locate a G root on another string using the full G major map. Find the same seven note names from that new starting point. This connects the tuning, the sound of the scale and the fretboard layout.
Practise one position, then connect the next
Begin with the full fretboard view and locate each G root note. Select Position 1, play its tab slowly in both directions, and say the note names as you play. Then select the next position and find the notes shared by the two areas before increasing the tempo.
Open tunings can make a chord or drone sound from open strings while a melody moves on the fretted strings. Keep the root notes in view when practising so the scale remains connected to the key, especially when moving between positions.
Compare scales in the same tuning
Keeping Open G selected while changing the scale makes it easier to hear how the interval pattern changes without also changing the tuning. You can also keep the scale fixed and change the key to see how the root moves across the neck.
Use the guitar scale finder to choose another key, scale or tuning. The related pages on each map provide direct links to nearby keys and other tunings.