Playing Shell chords is a concept that most students of jazz piano will come across at some point or another. If you study the masters from the past, most of them played Shell chords frequently.

It can be very beneficial to learn the different Shell chords in all the keys systematically.

The picture shows an Fmi7 chord played as a Shell chord.

WHAT ARE SHELL CHORDS?
The funny thing about Shell chords is that once you play them, the shape of your hand is similar to a shell. For the most part, you play the shells with your left hand.

The idea behind the Shell chords is to play the important notes and make musical sense. (More on that soon.)
If you play a C7 and you play it as C-E-G-Bb, the first thing that I would recommend that you do is to stop playing the G altogether on all the dominant seven chords. It is just in the way when you're improvising. Also, it does not sound that good (in my personal opinion) when you play the G on a C7 chord. (It works better to add the G when you play a wide chord with two hands over two octaves.)

You can strip down a C7 chord to two- or three- notes shells.

TWO NOTE SHELLS

Let's use a C7 as an example.

The most common way to play two-note shells is to play the root + the b7. The picture shows how you can play a C7 with just two notes.
Since you don't play the third (or fifth), you don't know the gender of the chord. Technically this chord could have been both a Cmi7 and a C7. That is why it is essential to consider the CONTEXT where you play the chords.

Another way to play a C7 is to omit the 7th altogether.
Technically, it is not a C7 if you don't play the 7th, but just as with the previous example, we should consider that it all depends on the context of where you play the chord.

Both of the previous images show a C7, played with two different voicings, examples of two-note shells.

Another variant that is used a lot by many is the rootless variant.
In this example, you don't play the root. Usually, this voicing will be used once we play with a Bassist. (Who plays the root.)

THE MAGIC OF THE SHELL CHORDS

The most exciting thing about the Shell chords is how the top note leads so well to the next chord with minor movements

The image above shows C7-F7-Bb7-Eb7-Ab7-Db7. (The exercise continues through the circle of fifths.)

Similarly, you can play Shell chords through the circle of fifths as rootless voicings by playing C7 as Bb+E, F7 as A+Eb, Bb7 as Ab+D, etc. In other words, you play the tritone interval descending chromatically. Also, it can be beneficial to practice this voicing ascending.

THREE-NOTES SHELLS

The first time I tried to copy a jazz musician that played three-note Shell chords, I could not do it in one go. If your piano keys are too large for your hands, there are things that you can do about it. I will cover this topic in another video.

For now, if you cannot reach the 10th at once with the 7th added, I suggest you roll it out quickly instead.

Variant 1
The three-notes shells are usually played as 1, b7, and 10, as shown in the image above.

Variant 2
You can also play a C7 as 1, 3, and b7.
I recommend that you practice the three-notes shells where you use both variants.

The image shows Variant two to variant one.
Please note: You can start on Variant one and then two on every other chord.

PRACTICE THE SHELLS THROUGH OFTEN PLAYED CHORD CHANGES.

Once you know the basics of Shell chords, I recommend that you practice the Shell chords through essential cycles.

Here is an example:

The image shows how you can play the Shell chords as a II-V progression, moving down (then up) in whole-tone steps.
There are plenty of variations you can learn, and I have made exercises of the ones that I find to be the most useful.



MAKE THE SHELL CHORDS SWING, AND APPLY THEM TO JAZZ STANDARDS

One last tip is to practice the shell exercises with a swing feel. I highly recommend that you use a metronome.
Once you know the basics and some of the exercises, you can try to apply them to jazz standard tunes.

ADD THE SHELL CHORDS AS PASSING-CHORDS

To most jazz standards, you can add passing chords as Shell chords. A passing chord is simply a chord that you play before landing on the target chord. Usually, you can play a chord one half-step above, a whole step above, and sometimes a half or whole step under the target chord.

The image to the right shows an example where I played a D7 before the Dbmaj7 in All The Things You Are. In this case, I played a Dominant 7 chord before the target chord (Dbmaj7.) Instead, I could have played a Dmaj7. The choice of chords depends on the melody and the sound you want to produce. The only way to figure it out is to experiment with the many options we have as jazz musicians.

I wish you good luck with the Shell chords.