Blues Harmonica Music Theory

Last I touched upon some arguments about music theory. This week I will give you a quick primer of the blues harmonica music theory you need to know to become an even better player. As you will see it is not very complicated and the benefits are well worth it.

Structure and chords of the 12 bar blues

The most common form of accompaniment you will come across when playing blues is the 12 bar blues. The picture shows the 12 bar blues outline with roman numerals and writing it like this means it can be used in any key.

Blues Harmonica Music Theory 12 bar blues outline

12 bar blues outline in roman numerals

  • I is the tonic chord of the key, based on the first note of the scale
  • IV is the sub-dominant chord of the key, based on the fourth note of the scale
  • V is the dominant chord of the key based on the fifth note of the scale

More on chords

A chord is two or more tones played together taken from a scale and the chords in a major key are based on the tones of the major diatonic scale. A G-chord is made up of notes from the G-major scale, a C-chord is made up of notes from the C-major scale and a D-chord is made up of notes from the D-major scale. What is often referred to as a chord is the first, third and fifth note of the scale played together. Stacking every second not of the scale is usually how it’s done (we won’t dive super deep into this). There is one exception however and that is that the seventh note of the scale i flattened when it is included in a chord. This makes the chord sound more interesting.

For the key of G (second position on a C harmonica) these are the chords:

  • I is G (found on a holes 1-3 draw on a C-harmonica)
  • IV is C (found on a holes 1-3, 4-6, 7-9 exhale on a C-harmonica)
  • V is D (not found as a complete chord on a C-harmonica, root note on 1, 4, 8)

Chord tones

To be able to use the knowledge of the chords further, it is a good idea to know where to find the chord tones on the harmonica. This blues harmonica music theory knowledge is second position specific and carries over when you change key as you then change the harmonica as well to stay in second position. Knowing the chord tones is especially important for the V-chord as few of the chord tones are in the blues scale (covered below). For each chord the cord tones are (key of G, although best to think of them as root, third, fifth and flat seventh):

  • I-chord G, B, D, F (root, third, fifth and flat seventh)
  • IV-chord C, E, G, Bb
  • V-chord D, F#, A, C

For the I-chord (read about harmonica tabs here):

  • G (root note) 2, 3+, 6+, 9+
  • B (third) 3, 7, (10+’)
  • D (fifth) 1, 4, 8
  • F (flat seventh) 2”, 5, 9

For the IV-chord:

  • C 1+, 4+, 7+, 10+
  • E 2+, 5+, 8+
  • G 2, 3+, 6+, 9+
  • Bb 3′, (6+o (overblow)), (10+”)

For the V-chord:

  • D 1, 4, 8
  • F# 2′, (5+o (overblow)), (9+’)
  • A 3”, 6, 10
  • C 1+, 4+, 7+, 10+

The notes on parenthesis are overblows and blow bends and if you do not master those techniques just ignore them.

Blues scale

The blues scale is probably the most common piece of practical blues harmonica music theory that people do learn. It gives a safe path to a bluesy sound over the 12-bar blues. The blues scale is based on the I-chord and the minor pentatonic scale connected to that chord. In addition to that scale the minor fifth is added which is a note that creates a lot of tension. It is known as tritone or “the Devil’s Interval”. The blues scale is made up of the following scale degrees:

Root, minor third, fourth, minor fifth, fifth, minor seventh


R, b3, 4, b5, 5, b7

On the harmonica this translates to:

1+, 1′, 1, 2”, 2, 3′, 4+, 4′, 4, 5, 6+, (6′, 6,) 7+, 8, 9, 9+’, 9+, 10+”, 10+
4, b5, 5, b7, R, b3, 4, b5, 5, b7, R, (b2, 2,) 4, 5, b7, R, b3, 4

Note: The holes and tones in parentesis are often added to make the scale more flowing as the b3 and b5 are missing between holes 6 and 9. This adds a little extra bluesiness to this range.

To make it a little bit more readable, here is the scale between holes 2 and 6.

2, 3′, 4+, 4′, 4, 5, 6+
R, b3, 4, b5, 5, b7, R

Blue notes

Blue notes are notes that create nice bluesy tension towards the chord. These are b3, b5 and b7. The blues scale contain these notes for the I-chord but also knowing them for the IV-chord and V-chord gives you nice option to play over those chords.

For the I-chord:

  • b3 3′, (6+o (overblow)), (10+”)
  • b5 1′, 4′
  • b7 2”, 5, 9

For the IV-chord:

  • b3 8+’
  • b5 2′, (5+o (overblow)), (9+’)
  • b7 3′, (6+o (overblow)), (10+”)

For the V-chord:

  • b3 2”, 5′, 9
  • b5 3”’, 6′
  • b7 1+, 4+, 7+, 10+

Benefits of blues harmonica music theory for soloing

Playing solos that completely stay within is absolutely fine but using chord tones and blue notes to follow the chords and mark chord changes for example can really create awesome solos. Especially how you handle to V-chord can set you apart from the rest of the pack. Here knowing the chord tones is cruical.

Benefits of blues harmonica music theory for accompaniment playing

When playing accompaniment playing you have a few options on what to play. However you chose to play it is your job to play something that is musically appropriate. You can for example play a bass line together with the bass player and then you will definately need to know where the chord tones are. Another option is to create tension against the chords and then you need to use blue notes and stay away from the chord tones. However you chose to play, know the theory will help you.

Putting it to use

I hope I have convinced you that learning blues harmonica music theory is a good thing and you want to make use of it. What you need to do now is take each of the concepts in this article, comit it to memory and start using it. The best way to do this is to concentrate on one single thing and have that as a focus when practicing playing solos for example. If you want to get to know the chord tones then play a lot of solos just using chord tones, when that starts becoming natural start using a few blue notes and so on. Before you know it this will become second nature.

Should you want to learn more general music theory I can recommend “Music Theory for Dummies” as a good starting point or you can take music theory classes on Skillshare (take advantage of the Premium membership offer).

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Music Theory – Pros and Cons

Music theory may not be at the top of your mind when you start playing blues harmonica. Some people even argue that knowing theory is bad. When I started playing I didn’t study any theory at all but during the last couple of years I have discovered the benefits. In this article I give you some counter arguments to arguments against knowing music theory.

Arguments against music theory

I have come across a few arguments against music theory for blues haromica players and I just want to make a few comments.

The masters got by without knowing theory.

Although it might be true that the masters of the early and mid 20th century were not classically trained in music theory, they certainly had a good intuitive grasp of it. They were learning from each other and other musicians and learned what sounded good. They learned it in practice. Most of us don’t spend as much time practicing and gigging as many of the early masters did. Learning theory is a way for us to leapfrog some of the trial and error.

I just play by ear.

Playing by ear is great and training your ears is a great thing. However theory will not hurt your by ear playing, it will just increase your understanding.

I don’t want to know music theory.

This argument I have the most difficulty understanding. I think it comes from a view that learning to play purely by ear is more noble and that music theory will hamper creativity. I would say that knowing theory increases creativity. You have to know the rules before you can break them with good effect.

It will stop me from being creative.

Actually I would say that knowing more allows you to be more creative. It allows you to utilize riffs and musical passages that you never would have thought of if the theoretical connections hadn’t been there.

Music theory pros

Understanding more of what you do is always a benefit in my opinion. More knowledge changes how we see things and we often end up enjoying it more. We also get a new vocabualry that we can use when communicating with other musicians. It is definately beneficial to be able to communicate with a musicians vocabulary in a open stage situation or if you gig with somebody you normally don’t play with.

Music theory cons

I don’t really see any cons with knowing a bit of theory. The only thing might be that when you pratice to internalize it you might feel like you have taken a step back. Don’t worry, it is just temporary.

What next?

Next week I will continue this topic and outline the few things you need to know as a blues harmonica player. You will see that it is not all that much and not very complicated. I will also tell you more about the benfits of knowing a little bit of music theory. Sign up below so that you don’t miss when that article comes out!

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Blues Harmonica Positions at a Glance

I often get questions about different positions when playing blues harmonica. Most beginning players learn to play second position, for a very good reason, and never really think about why. To be honest, you probably don’t have to know why but I tend to think that expanding your knowledge is always good. It will make you a better player even if you take pride in playing by ear and play what you feel. Another thing I have noticed is that some of the information being tossed around is sometimes misleading. In this article I will give you my view of why we use different positions. I hope this information will help you chose which harmonicas to buy.

Harmonica theory

First some theory. When playing blues we tend to focus our playing around the blues scale. This because that gives us a very nice sound and keeps us in tune. The blues scale is formed by adding the flatted fifth to the minor pentatonic scale. R b3 4 b5 5 b7. In C this would be C Eb F Gb G Bb. If you play blues in C this is the blues scale no matter what position you play in. I sometimes come across the misconception that the scale is different depending on the position, it is not. However you may not always have access to the complete scale in the position you have chosen. Still, the scale itself stays the same. This takes me to the first reason we might choose a specific position.


Choosing a position based on convenience is sort of like a guitar player that doesn’t like playing in F using a capo on the first fret to be able to use the same fingering as in E. Everything becomes easier.

First position

If you map the C blues scale to a C harmonica you will notice that some of the notes are hard to play. I am not including overbends/overblows here since that is quite advanced. Usually not something you master early in your blues harmonica career.

On holes 1-3 you can get R, 4, b5, 5 and b7 on 1+, 2”, 2′, 2 (or 3+) and 3′. So almost a complete scale, only missing the flatted 3rd. On holes 4-7 though you get R, 4 and 5 so you are missing all blue notes. Not a good place to start. On holes 7-10 things are better again and you get R, b3, 4, b5, 5 and b7 for a complete blues scale on 7+, 8+’, 9, 9+’, 9+ and 10+”. However you end up with quite a bit of blow bending which may take you some time to get right. So even if you can play in first position it will present some challenges and it won’t be the the first choice for beginners.

Second position

If instead you map the C blues scale on an F harp, known as second position, you get the root note on hole 2 inhale and you get a complete blues scale easily accessible on holes 2-6. R, b3, 4, b5, 5, b7 are found on 2, 3′, 4+, 4′, 4, 5, 6+. This means that a lot of the notes you need are there “for free”. This is one of the reasons second position is so popular, you can master the blues scale quite quickly in this position. Another good thing is that two of the chords the band plays, the C (the I-chord) and F (the IV-chord), are available on holes 1-3 inhale and exhale. This means that you can switch between playing single tones and chords and be in tune easily with the band. Playing chords give you a BIG sound which is what you are looking for.

If you dig a little deeper you will find that all inhale tones work well with the I-chord and all exhaling tones are chord tones of the IV-chord and also work OK with the I-chord. This means that almost anything you play will sound good over a standard 12-bar blues, at least it will not be out of tune. Also, since many tones are chord tones you can use a lot of two-tone combinations (partial chords) for a nice bluesy sound and texture. The 2-5 split is especially nice since it is the R-b7 combination, very bluesy.

Weakness of second position

There is one thing second position isn’t very suited for and that is playing in minor. You can do it but it puts high demand on your bending skills since the b3 located on 3′ really has to be in tune. If you play it sharp it really sounds awful, this is the reason most players don’t play minor in second position. Also, the chords you play on holes 1-3 are major chords so you cannot use them the same way. It is not true however that you cannot play minor in second position, it is just more difficult and if you play the same as for a major song you will get into trouble.

Third position

Now let’s look at third position really quickly. Probably the second most used position today for blues harmonica. Many people think this position is only for minor blues which is not true, it works very well for major blues as well but it is often used for minor blues because it is easier to play well in minor compared to second position. On holes 1-4 you find the blues scale on 1, 2”, 2, 3”’, 3”, 4+. A lot of bending in this range, Holes 4-7 is easier, 4, 5, 6+, 6′, 6, 7+. In this range you basically get all important tones “for free”.

The b3 which you need to play in key for minor is on 5 so you don’t have to worry to much about playing it sharp. Also holes 4-6 played simultansously is the i-chord (minor chord). Holes 8-10 gives you a partial scale. R, b3, 4, 5, b7 on 8, 9, 9+, 10, 10+. Again very easy to control and the i-chord is on 8-10 inhale. You also have the R-b3 partial chord on 3+-4+, 6+-7+ and 9+-10+. So from  hole 4 and above this is a very easy position even in minor, the low octave takes requires som bending skills.

Now on to another reason to select a certain position.

Tonal range

If you only play second position you will in some keys end up with a tonal range you don’t feel comfortable with. For example, if the band plays in C and you only play second position you either have to use an F-harp which is very high in pitch or a low-F-harp whcih is quite low. Maybe neither is appropriate for the song or maybe you don’t feel comfortable playing thiose harps. Choosing third position instead puts you on a Bb-harmonica instead and all of a sudden you are playing a mid-range harmonica instead.

Next reason…

The feel

Depending on how the blues scales is laid out on the harmonica in different positions and which techniques are available, the positions have different feels. For example, third position is often said to be a bit darker than second position. One of the reasons for this is that the b3 is easier to play right in pitch emphasising the minor quality. Fifth position also sounds quite dark with the root note on 2+.

Expanding your lick vocabulary

When working with other positions than second you will learn new licks that will be useful also in second position. For example when you play over the IV-chord in seconds position you can use any first position lick you have learned. When you play over the V-chord you can use any third position lick you have learned. This really expands your vocabulary and will introduce licks you otherwise may never have used.

Your harp preference

Maybe you have a favorite harmonica or don’t have the appropriate second position harmonica available. Playing in another position can save you here and offer more options.

Giving yourself a challenge

When you have been playing for a while going to a new postion is a good way to develop your skills and give you new ideas. Also it will be easier for you to tackle non-standard blues if you are used to playing over more chords than the standard I-IV-V chords in second position.


I hope this gives you an idea about position playing on the harmonica and takes some of the mystery out of it. If you have any thought or comments on this contact me via e-mail or post a comment below. I will help you as best I can. I have also created a a downloadable PDF for you mapping the blues scale in all positions. It also lists the connection between harmonica-keys and the keys of the different positions. Sign-up to my e-mail-list below to get it. You also get a Udemy discount code.

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