> For the complete documentation index, see [llms.txt](https://music.davidjaybuckley.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://music.davidjaybuckley.com/instrument/jazz-piano/jazz-chords/the-shell.md). # A. The Shell and Chord Theory ## Introduction As a jazz pianist, one of the main jobs that you have is to play the harmony to support the melody instruments. To do this, you need to understand how chords work. ## Basic Chord Theory The first way that you should understand chords is by stacking thirds in root position (meaning that the lowest note is the root note). Below is a chart to help you visualize all the possible notes in a chord. The most important kinds of chords to know are the ones in bold below (labelled I, ii, and V), being able to play the **root, 3rd,** and **7th** of the chord. The **3rd** and **7th** played together is known as [**The Shell**](/instrument/jazz-piano/jazz-chords/the-shell.md#playing-the-shell). The Shell defines the *quality* and *function* of the chord (major, minor, or dominant) and you do not need any other notes to get that idea across. You may choose to add notes to alter or color the chord, but that will not change its identity as major, minor, or dominant. Each note in a chord is assigned a number, and when you build chords in thirds, each number is odd starting at 1 and ending at 13. The notes 1, 3, 5, and 7 are the basic structure to the chord. The notes 9, 11, and 13 are **Upper Extensions** and add color to the chord. The upper extensions (and the 5th) are sometimes [altered](/instrument/jazz-piano/jazz-chords/voicings.md#alterations) (sharpened or flattened), especially on dominant chords for good voice leading and coloration. {% hint style="info" %} In the sheet music below, check out how to build major, minor, and dominant chords by stacking thirds. Most importantly, *scroll down to see the Root + Shell* (3rd and 7th, in root position) to see what notes are in each chord. When you actually play these chords in a song, learn to [voice](/instrument/jazz-piano/jazz-chords/voicings.md) them in many different ways. {% endhint %} {% embed url="" %} {% file src="/files/-M8MDge9cIOWkZZ\_o74Z" %} Jazz Chord Construction {% endfile %} ### Simplifying Complicated Chords Now, even though we are focusing on playing the shell (root, 3, 7) right now, as you play songs, you might encounter chords that have extensions or look different. Here's how to replace some of those chords with simple major, minor, and dominant seven chords. Simplifying chords into groups of major, minor, and dominant is a useful skill for pianists of all skill levels because knowing the quality will influence the substitutions, scales, sounds, and most importantly the *function* of what you play. | Chord | Replacement 7th chord (shell) | | --------------------------- | ----------------------------- | | D9, D11, D13 | D7 (dominant) | | F6, F6/9, Fmaj9, Fmaj13 | Fmaj7 (major) | | Am6, Am6/9, Am9, Am11, Am13 | Am7 (minor) | Diminished and augmented chords alter the fifth of the chord, so if you do these replacements, ensure that you do not include the fifth unless you properly alter it. | Chord | Replacement 7th chord (shell) | | -------------------------------- | ----------------------------------------------------------------------------------------------------- | | Caug (aka C+, augmented) | C7 (dominant) | | Bm7b5 (aka B𝆩, half-diminished) | Bm7 (minor) | | Edim (aka E°, diminished) |

C7 (dominant)

The root with the dim chord becomes

the 3rd of the dominant chord.

| Finally, any chords with altered upper extensions attached to them can be reduced by dropping the alterations. | Chord | Replacement 7th chord (shell) | | ------------------------- | ----------------------------- | | D7#11, D7b9, D7#9#5, etc. | D7 (dominant) | ## Playing The Shell in a ii-V-I The first way to practice jazz chords is by playing the shell, which is the 3rd and 7th of the chord. ### Major ii-V-I The progression outlined below is called a Major$$ii$$-$$V$$-$$I$$(or just$$ii$$-$$V$$-$$I$$, pronounced 2, 5, 1). The$$ii$$chord is minor, the$$V$$chord is dominant and the$$I$$chord is major. In the sheet below, the six ($$VI$$) chord is optional; you may play it if you want to repeat the measure to take you back to the$$ii$$chord. 1. Practice the shell in the right hand by itself. 2. Practice playing the shell in the right hand with the root in the left hand to internalize the sound of these chords with a bassist. 3. Practice playing the shell in the left hand by itself. {% embed url="" %} {% file src="/files/-M8MBEAg04FNX\_aurF-T" %} Major ii V I (shell) {% endfile %} ### Minor ii𝆩-V-i Do the same practice routine as the major ii-V-I for the minor ii𝆩-V-i below. {% embed url="" %} {% file src="/files/-M8MCpfLyb2hzSVNqPiO" %} Minor ii𝆩-V-i (shell) {% endfile %} ## Learning Tunes When you take your new-found harmony skills and decide to learn some tunes, here is a four-step process to mastering that tune. For each step, practice with a metronome and practice hands separately as needed. 1. Melody (RH) + Bass line roots only (LH). 2. Shell (RH) + Bass line roots only (LH). 3. Melody (RH) + Shell (LH). 4. Melody + Shell + Bass (spread across hands). The first two steps are to help you understand the song and hear how the harmony and melody works together. The third and fourth steps are especially useful for solo piano practice and preparing to improvise over the tune. --- # Agent Instructions This documentation is published with GitBook. GitBook is the documentation platform designed so that both humans and AI agents can read, navigate, and reason over technical content effectively. Learn more at gitbook.com. ## Querying This Documentation If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question. Perform an HTTP GET request on the current page URL with the `ask` query parameter: ``` GET https://music.davidjaybuckley.com/instrument/jazz-piano/jazz-chords/the-shell.md?ask= ``` The question should be specific, self-contained, and written in natural language. The response will contain a direct answer to the question and relevant excerpts and sources from the documentation. Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.