Hello, everyone.
Thanks to everyone for watching this video.
My name is Qi Dang.
I am an amateur musician.
Today's video is titled chord progressions
and it is going to provide you the understanding of scale-based chords,
fitting chords to a melody, and a melody to a chord progression.
I am going to give you an overview of what I am covering today's video.
First at all, it is an introduction of chords.
And then focus on the chord progression before wrapping up with conclusions.
More often than not, music is more than a single melodic line.
Music is a package of tones, rhythms, and underlying harmonic structure.
The harmonic structure of a piece of music is defined by a series of chords.
A chord is a group of notes played simultaneously, rather than sequentially (like a melody).
The relationships between the notes, the intervals within the chord, define the type of chord;
the placement of the chord within the underlying key or scale defines the role of the chord.
What is the chord? A chord is a combination of three or more notes played together.
Basic chords consist of just three notes, arranged in thirds, called a triad.
The most common triads are constructed from notes plucked from the underlying scale, each note two steps above the previous note.
Chords can also include more than three notes.
When you get above the basic triad, the other notes you add to a chord are called extensions.
We have seventh chord, ninth chord, eleventh chord and thirteenth chord.
Individual chords alone are interesting, but they become really useful when you string them together to form a succession of chords,
what we call a chord progression.
These chord progressions provide the harmonic underpinning of a song, "fattening out" the melody and propelling the music forward.
Of course, to create a chord progression that sounds natural, you can't just string a bunch of chords together willy-nilly.
Certain chords naturally lead to other chords; certain chords perform distinct functions within a song.
You have to use your chords properly, and arrange them in the right order,
to create a piece of music that sounds both natural and logical. Like this.
If we add sub-dominant chords, you can feel the music sounds more interesting.
Now we can move to chord progressions.
If we list the scales of C major, then each note is made into a triad, and you will get these seven chords.
These chords can naturally occur in C major without adding key signatures.
What we are going to discuss today is what role these seven chords play in C major.
Initially, we can listen to a piece of "Little Star".
The first and last chord of this piece are C major. We called the first chord as the tonic chord. 
This chord has a feeling of at the beginning, or at the end, or a sense of stability.
We can say the tonic chord as "home". If we use this chord in this tune, then it will be boring.
Therefore, in order to avoid this situation, we need an unstable chord to contrast with the tonic chord.
This chord is the fifth of this list. We called the dominant chord.
The feeling of the dominant chord is the opposite of the tonic chord.
It is neither the beginning nor the end, so it is an unstable feeling. We can call it as "outside".
We now play from the C to the G, and back from the G. We are starting from home.
Now we go home from the outside. This will feel like at the end.
If there are only two chords, it will still be boring when we just listen to the two chords for a long time.
So, we need to have an additional chord, at the position of the fourth chord, which is the F chord in C major. 
This chord has a feeling of intermediation. It likes to take a step from the tonic chord.
Then, we can use it to connect the dominant chord. We can call it as "bridge".
"Home", "outside" and "bridge" are the most basic chords. G7 is also a dominant chord. Let's listen to a chord progression of C-F-G7-C.
We can start from home, walk on a bridge, go outside, and go home.
Currently, we have another four chords, and they have not been defined. What are the functions of the remaining four chords?
In fact, instead of giving each chord a function, it is better to classify all chords into the three functions that we described.
When we write chord progressions, it becomes very simple. So, we just need to classify the remaining four chords,
which one likes home, which one likes outside, which one likes bridge.
Now we can see the seventh chord, the B minor triad chord.
It sounds like outside.
Next, it's the fifth chord, D minor chord.
It sounds like bridge.
D minor has bridge function, so we fill it in the list of bridge candidates.
Now we have two chords for bridge and outside.
So, the route from home to home becomes four possibilities. The four routes have different feelings.
Next, it's the third and sixth chord.
These two chords don't sound like home. Like friend's home or hotel, and it doesn't like long-term residence.
So, we fill A minor and E minor in the first grid of this table, and in the rightmost grid.
When A minor and E minor are used as extensions of home, they can also be connected to each other.
For example, we can connect C to E minor to A minor.
The two bridges can also be connected to each other. So, we then fill in F to D minor, or D minor to F.
Now we look at this table. There are five possibilities for home, four for bridge, two for outside, and three for going home.
So, the number of route possibility from home to home is five times four times two times three, a total of 120.
You can choose any one of these 120 routes to sound very smooth harmony.
Let's try one of them. For example, we can connect C to E minor, to A minor, to F, D minor, G7 and C. Like this.
Listen again. We now start from home, then to our friend's house, and then to the hotel to have a break.
Then, we feel uncomfortable outside and want to go home. Finally, we go home.
These are all chord functions that we described.
From conclusions what we learned,
a chord consists of three or more notes played simultaneously with each note typically a third above the previous note.
Every note of the scale has an associated chord. Chord progressions naturally lead back to the tonic, chord of the underlying scale.
Okay, thanks to everyone for watching my video today
and I do hope you found the video informative
and that you learned somethings from it.
If you do have any questions, then you can write comments and messages.
I am happy to answer any questions.
Thanks for your watching!
