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Th e "Minor 2 5" - aka IIø V7 or IIm7b5 V7b9

The “Minor 2 5” series is part of my da’play program where I share musical insights and some of my personal practice tracks with others including my students, btw, my teacher profile can be found on:

“Minor 2 5” refers to the chord degrees that can be found in a minor key. For example in the key of A Minor, with the scale notes A B C D E F G A, there are chords for each of the scale notes and these notes are numbered from 1 to 7, often written in Roman numerals, and when we talk about the numbers in relation to those chords, we would say “1st degree”, “2nd degree”, etc.

Roman Numeral SpokenScaleChordSpoken
I1AAmA Minor
II2BB Diminished
IV4DDmD Minor
V5EEmE Minor
VI6FFF Major

In this Minor 2 5 series we’re focusing for the most part on just the two chords that form the typical “minor 2 5”, “minor II – V” or “IIm – V”, or to be more precise the “IIm7b5 – V7b9”.

These two chords appear on the second and fifth degree of a minor scale. For example, in the key of A minor with the notes: A B C D E F G A, the second degree would be the chord based on B and the fifth degree would be the chord based on E.

The chord or triad starting on B would contain the notes B D F (1 3 5 starting from B), the quad (1 3 5 7) would include the note A as well, so B D F A.
Looking at those notes and their intervals to B we can see that they are: unison, minor third, diminished fifth and minor seventh, 1 b3 b5 b7, which is almost the same structure as found in a minor 7th chord 1 b3 5 b7, but with the difference of the b5. Therefore, this chord is often written as Bm7b5 chord or as the so-called “half-diminished” chord with the symbol Bø or Bø7.

The chord on the fifth degree starting on E and containing the notes E G B, with 1 b3 5, is a minor chord. However, it is common to borrow the note G♯ from the A Harmonic Minor scale: A B C D E F G♯ A, to create a major chord on the fifth degree with E G♯ B. The G♯ then becomes the leading note of the A minor scale, and therefore this E chord functions like a dominant V chord for the Am tonic chord.

If we add the 7th to the E chord we get E G♯ B D (1 3 5 b7), which is indeed a typical dominant V7 chord: E7.

The b9 in the chord symbol is just a little reference to the fact that we are in the context of A minor where the next note after E is F, which is just a semitone above from E, hence it’s referred to as a b9 (or sometimes as b2).
When playing the 7b9 chords it is optional whether to play the b9 or not. Just because b9 is written as part of the chord symbol does not mean that it must be always played or heard. In fact, this really is more of a reminder of the harmonic context of the minor scale, i.e. something to ‘keep in mind’ whilst playing. (See below for more on that.)

A useful approach to improvising is to view the notes of the chords as a foundation. Memorising what these notes are and where to find them on the instrument is a good starting point.

[You may find the idea of memorising notes for each chord a little daunting still, and at first you could simply play the notes of the corresponding Harmonic Minor scale to get a first feel for this. See the table below with a list of all corresponding Harmonic Minor scales and their notes.]

key clock

The complete Minor 2 5 series contains twelve tracks, one for each key. The table here lists all of the chord tones for the keys in the order of the tracks in the playlist, starting with no sharps or flats, and then going up in number for flats and sharps. In terms of the circle of fifths expressed as a clock, the first track would be for 12 o’clock (C Major/A Minor), the next two tracks are for 11 o’clock (F Major/D Minor) and 1 o’clock (G Major/E Minor), both have one flat or sharp.
Followed by  10 o’clock and 2 o’clock for (Bb Major/G Minor) and (D Major/B Minor), with two flats or sharps respectively, and so on.

KeyHow many # or ♭IIm7b51♭3♭5♭7V7135♭7♭9
A MinorBm7♭5BDFAE7♭9EG#BDF
D Minor1♭Em7♭5EGB♭DA7♭9AC#EGB♭
E Minor1#F♯m7♭5F♯ACEB7♭9BD#F♯AC
G Minor2♭Am7♭5ACE♭GD7♭9DF#ACE♭
B Minor2#C♯m7♭5C♯EGBF#7♭9F#A#C♯EG
C Minor3♭Dm7♭5DFA♭CG7♭9GBDFA♭
F# Minor3#G♯m7♭5G♯BDF♯C#7♭9C#E#G♯BD
F Minor1♭Gm7♭5GB♭D♭FC7♭9CEGB♭D♭
C# Minor4#D♯m7♭5D♯F♯AC♯G#7♭9G#B#D♯F#A
D♭ Minor8♭E♭m7♭5E♭G♭B♭♭D♭A♭7♭9A♭CE♭G♭B♭♭
B♭ Minor5♭Cm7♭5CE♭G♭B♭F7♭9FACE♭G♭
G# Minor5#A♯m7♭5A♯C♯EG♯D#7♭9D#F##A♯C#E
A♭ Minor7♭B♭m7♭5B♭D♭F♭A♭E♭7♭9E♭GB♭D♭F♭
E♭ Minor6♭Fm7♭5FA♭C♭E♭B♭7♭9B♭DFAC♭
D# Minor6#E♯m7♭5E♯G♯BD♯A#7♭9A#C##E♯G#B

Step 1: Play the track and memorise the notes for each arpeggio and be able to find them quickly on your instrument.
At the beginning of each track you have 8 bars for each chord to get to know where those arpeggio notes are. As the track continues, you have less and less bars to find and create melodic phrases that match the chord.

Step 2: Adding notes, adding “flavours”:

For example, when you use the notes of the Bm7b5 arpeggio B D F A as a skeleton frame for your melodies you might want to add some other notes to expand your ideas. You could simply add the notes of the corresponding Harmonic or Natural Minor scale, which would be A Harmonic Minor or A Natural Minor here:

With A Harmonic Minor: B C D E F G♯ A
With A Natural Minor: B C D E F G A

This would work quite easily. However there is another way of looking at this:

Between the notes B and D there are the two notes C and C♯. If you wanted to decide which of these two notes you would prefer to play today (tomorrow, you might change your mind), you could play B C D, followed by B C♯ D and then make a decision on whether to include the C note or the C♯ note. In theory, if you combined that with the Harmonic and Natural Minor scales, you would have four scale options:

Using C:
With A Harmonic Minor: B C D E F G♯ A
With A Natural Minor: B C D E F G A

Using C♯:
With A Harmonic Minor: B C♯ D E F G♯ A
With A Natural Minor: B C♯ D E F G A

In a way, we already did the same thing when we thought of using either the Harmonic with G♯ or the Natural Minor scale with G. Between F and A you can play either G or G♯ (or both if you wish).

And this is how the concept works: Make sure you know your “frame”, the notes contained in the chord, very well, and then add some ‘in between’ notes. Make a decision which of those in between notes you prefer to play (in that moment).

For Bm7b5 you have three points where you could choose between:

1) G or G♯ (or both)
2) C or C♯ (or both)
3) Eb or E (or both)

By choosing which notes you want to include, you are also making a momentary scale choice. With G and G♯ you have already seen that these two notes decide on whether you are playing in Harmonic Minor or in Natural Minor (assuming the other note choices are C and E).

(Assuming G), choosing between C or C♯ decides whether the resulting scale would be either: 

Locrian: B C D E F G A
Locrian nat 9 / Aeolian b5: B C♯ D E F G A

By the way, the decision is yours. Some scales might lend themselves more to certain situations… a romantic ballad may work better with the Locrian scale, whereas a more neutral, story telling type tune may work better with the Locrian Nat 9 scale.
The choice is always yours!

3) Regarding Eb or E:
Eb is enharmonically the same as D♯, and with B as the root of the chord, the note D♯ would be the major third, which would change the character of the chord from a minor type chord to a major or dominant type chord, therefore D♯/Eb is rarely played as a strong note in the context of a m7b5 chord. However, as a short passing or chromatic approach that note could be played as well.

Assuming the note E is mostly chosen, our options are:


If you add the arpeggio notes B D F A, you will get complete scales, which are called :

BCDEFGABB Locrian7th mode of C Major
BCDEFG#ABB Locrian Natural 62nd mode of A Harmonic Minor
BC#DEFGABB Locrian Natural 2 / Aeolian b56th mode of D Melodic Minor
BC#DEFG#ABB Dorian b52nd mode of A Harmonic Major

All of this might seem complex, but the trick really is to simply focus on the chord notes and whichever notes you would like to add in between the chord notes. By the way, you are free to mix and match and you also don’t need to stick to a particular note or scale choice for any particular length of time.

Go to the next page to discover all the scales you can play over the E7b9 chord!

Improvise Like a Pro
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