It means to slow down. The relationship between 123456734 and 71 is the semitone rit: when you see this mark, it means that you need to slow down here. It is the abbreviation of ritardando, which roughly means that you can find it online yourself. Find semi tone, whole tone (Semi tone, whole tone) Divide an octave into twelve equal parts, each part is a semitone, and two semitones are equivalent to a whole tone. A semitone is equivalent to a minor second, and a whole tone is equivalent to a major second. Chromatic scale (chromatic scale) The distance between adjacent two tones is a "chromatic scale", which is called a "chromatic scale". Whole-tone scale (whole-tone sacale) The distance between two adjacent tones is a whole tone, which is called the "whole-tone scale".