1=G means that the music is in the key of G major.

G major is a major mode with G as the central note. The parallel minor is E minor, which is counted as a sharp in the staff.

The G natural major scale is G A B C D E #F G, which also includes G harmonic major and G melodic major. The G harmonic major scale is G A B C D E flat #F G, and G major is a sharp. Equivalent to Fa in the key of C sharp.

The ascending scale of G melodic major is written in the same way as the natural major, and the descending scale is lowered by the sixth and seventh steps. The scale is GA B C D E flat, which restores F and G. The parallel minor is e minor, and the related minor is C major, D major, a minor, b minor, and e minor.

G major is the seven notes of gabcde#f corresponding to 1234567 in simplified notation. Generally speaking, g1 to f2 correspond to 1234567 without adding a high or low point, and g to f1 correspond to 1234567 with only one low point. G to f corresponds to 1234567 with only two bass points added, g2 to f3 corresponds to 1234567 with only one treble point added, and g3 to f4 corresponds to 1234567 with only two treble points added.

Extended information

According to the system of twelve equal temperaments, we can start from any semitone (DO, #DO, RE, #RE, MI, FA, #FA, SOL, #SOL, LA, #LA, SI), create a new major key according to the order of intervals in the major key, taking C major as an example:

I　II　IIIIV　VVI　VII

Whole tone, whole tone, half tone, whole tone, whole tone, half tone

A, tonic, leading tone

Each major key has seven tones, and the Roman numerals you see are In the series we arrange for these seven notes, the first note is the I note, which is often called the "tonic" as the most important note in the entire major key, while the seventh note is the VII note, which guides the entire scale again. The VII note that returns to the tonic is often called the "lead note."

B. The composition rules of the major key

The interval size between each note is in the order of "whole-whole-half-whole-whole-whole-half". This This is the composition rule of the major key. We divide the entire scale into two parts: "DO, RE, MI, FA" and "SOL, LA, SI, DO", which are called "note patterns".

Each tone pattern contains four tones, and the interval distance between them is "whole, whole, half", so a major key is composed of two "whole, whole, half" tone patterns, with "whole, whole, half" in the middle. A whole tone is connected. The entire major scale consists of the oral formula: "whole and half, whole, whole and half."

Baidu Encyclopedia-Major Tune in Music Theory