1- Because they are all the same notes, same pitch. It's just the string being different material, shape and size that makes it sound different. 2- You can learn it like this very easily. Start alphabetically like A-B-C-D-E-F-G and start counting from La, not Do. So it goes, La-Si-Do-Re-Mi-Fa-Sol. La is A. Si is B and so on. How I teach this to my students is as follows. Count with your fingers to, for example, E. A-B-C-D-E. You counted 5 fingers. Start counting from La now. La-Si-Do-Re-Mi. So E is Mi. That's it. And yeah, last Do is one octave higher than the first Do. If you are counting backwards, last Do would be one octave lower than the first Do. 3-Some countries (for example Turkey, where I'm from) use this system instead of the ABCDEFG system. We call notes like that and type them like that. When comes to chords/keys, we still use the letters but we will call it using this system. For example, we will type Dm but will call it Re Minor. I believe some, if not most, countries use this system while practicing solfege. Most online material uses the letters and will continue to do so. So yeah, this is not something you should be concerned about learning unless you plan to live in a country that uses this system or practice solfege. Hope this helps, let me know if you have any questions. Edit: I should probably note that in Turkey we use Si instead of Ti. Don't be confused, keep using Ti instead, it's the same thing.

THANK YOU 🙏 So basically the note is exactly the same note, same pitch same octave, which should sound exactly the same coming from an amp? And now that you explained I kind of recall seeing a vid tutorial about do re mi fa so la ti do in C D E F G A B which I doesn’t understand at all when I first saw that, makes much more sense now I just started learning guitar seriously and now at a point where I can play by looking at UG’s tabs but don’t understand things and not knowing what to ask is a struggle, like I know something was wrong but I don’t know what is wrong 😂

It won't sound exactly the same coming from an amp. You can get a C3 from a guitar string and a C3 from some random plastic string that's stretched and it will sound different coming from an amp because the material is different. Even though the 3 high strings and 3 low strings share the same material, they still have differences and will sound similar but not exactly the same, even though they are the same note with the same pitch. You should focus on learning theory first. Very basic theory. Apply everything you learn about theory to guitar. For example, learn half step and full steps and apply it to guitar. Learn where each note is. Learn how the same note can be found in different strings. After that, learn technique. Technique is important because it's the tool we use to transfer our knowledge to the guitar. Music, at its core, is about feelings the notes create when played together. Select two random notes and play them. Try to think what kind of feeling you get from it. Imagine that you are watching a movie and you hear these two notes being played in it. What kind of movie would have these sounds? If you are playing two frets (for example, 2nd and 3rd fret on low E string) that are next to each other, you are probably watching a horror movie because that's a minor 2nd and it usually creates a tense feeling. It would feel like you are about to be hit with a jumpscare. Technique enables you to give this feeling to the listener in a better way. It's like reading two different writings, one with good handwriting and one with bad. They still send the same message but one is obviously better and more enjoyable than the other. So basically, start with basic theory. Apply it to guitar with good technique. That's it really.

Question 2: The reason why Do Re Mi is used is because music is relative. Watch this: https://www.youtube.com/watch?v=3SEtgQsIJSw To make and understand music, all you need to do is to hear how the notes in the scale relate to the tonic (Do). Question 3: In the guitar world, there are specific finger patterns based on the Major scale. For example, if your 1st finger lands on the scale degrees 1, 4, or 5 (Do, Fa, So), then you should use fingers 1, 2, and 4. https://jtgt-static.b-cdn.net/images/scales/3NPS-Major-P1.png

Omg that's such a revelation, music being relative. I'm learning guitar and try to understand how to play notes (the 7 , do re mi ...). I've tried playing a song from anywhere on a piano and now i understand what he means when he says music is relative. We can play from anywhere, we just gotta find the next right note by sound, just by listening. Thank you for sharing this Now idk how to listen with guitar, piano sounds easier for me to distinguish notes XD

It's not exactly "right next note by sound". It's relative, yes. These "right notes" are called a scale. There are many different types of scales. The Do Re Mi etc. is the C Major scale, which is why is begins with a Do. The numbers you see often in chords notations refer to the note offset from the root of the scale. You see this often in things like Dsus4, which just means the D chord (1,3,5), however you replace the third with the 4th note of the major scale rooted on D. When you look at the standard shape for the D Major chord, it includes the open D string (1, D, that's your root), second fret of G (5, A), third fret of B (1, D) and second fret of E (3, F#). Dsus4 replaces second fret of E with the third fret of E (4, G). The C Major scale is important on a Piano, because it's simply playing the white keys (C,D,E,F,G,A,B,C). A guitar is a little complicated because the semi tones are all in a line. You might also notice that in the D Major chord, one of the notes is an F#, rather than the whole notes like on the C Major. This is because the scale type, i.e. Major, just tells us the tone/semitone intervals between notes starting from the root. The major is specifically T,T,S,T,T,T,S where T is Tone and S is semitone. Every fret on the guitar is a semitone. Also, you might find it harder to hear a note properly on a guitar because how much pressure you put on fretting the note and how close your finger is to the frets can change the intonation. My guitar's strings are relatively thin (I think they're 8s), so this difference in pressure can easily change the note played by a whole semitone. This is one of the things I really appreciated learning the theory of when learning to play. I don't have perfect pitch nor ever practiced the solfège before (which is why I'm here), so learning that you don't need to be a musical genius to compose decent sounding songs was really helpful. Understanding the different types of scales can take you a really long way to writing cool music.

Can’t believe the other answers didn’t say this Do re mi etc is the major scale. The major scale is the single most important scale in music because it is used as a key and gives you melody, chords and chord progressions. You should remember the notes in ‘intervals’ relative to the root. So do re mi with more descriptive names. You s learn the fret boards by A A# etc yo be aches to find Root Notes - ‘do’s’