What is jazz? By Leonard Bernstein

A Master Maestro’s explanation and defence of Jazz

Flavio Musa de Freitas Guimarães
19 min readApr 29, 2022


Photo by The Marina at Cherry Creek

I love jazz.

This masterclass by Bernstein is on Youtube; you can listen by clicking on the link above.

For those who like Jazz, but don’t have time to listen, I paste the text of his speech here, with some small voice reading errors.


What is jazz?

by Leonard Bernstein

Take a Train

Now, anyone hearing this music, anyone on any civilized part of this Earth, east or west, pole to pole, would immediately say “That is jazz.”

We are going to try to investigate jazz, not through the usual historical approach of “up-the-river-from-New-Orleans,” etc. — which has become all too familiar — but through approaching the music itself. We are going to examine the musical innards of jazz, to find out, once and for all, what it is that sets it apart from all other music.

Jazz is a very big word, it covers a multitude of sounds, all the way from the earliest blues “oh, oh, I ain’t got no mammy now, oh, oh, I ain’t got no mammy now”[2], the Dixieland bands ..[3].., the Charleston bands ..[4].., the swing bands ..[5].. to boogie-woogie ..[6].., to crazy bop ..[7].., to cool bop ..[8].., to mambo ..[9].. and much more. It is all jazz and I love it all. I love it because it’s an original kind of emotional expression, in that it is never wholly sad or wholly happy. Even the blues has a robustness and a hardboiled quality that never lets it become sticky sentimental, no matter how self-pitying the words are. “I woke up this morning with an awful aching head, [repeat], My new man has left me just a room and an empty bed”[10] and, on the other hand, the gayest, wildest jazz always seems to have some hint of pain in it. Listen to this trumpet and see what I mean …[11]

That is what intrigues me about jazz: it’s unique, a form of expression all its own.

Then I love it for its humour. It really “plays” with notes.

We always speak of playing music. We play drums, we play Bach. It’s a term perhaps more properly applied to tennis, but jazz is real play; it fools around with notes, so to speak; it has fun with them; it is therefore, entertainment in its truest sense.

But I find I have to defend jazz to those, for instance, who say it is low class. But then all music has low-class origins since it comes from folk music which is necessarily earthy; after all, Haydn’s minuets are only a refinement of simple, rustic, German dances and so are Beethoven’s scherzos. An aria in a Verdi opera can often be traced back to the most basic Neapolitan fishermen. Besides, there has always been a certain shadow of indignity around music, particularly around the players of music. I suppose that is due to the fact that historically, players of music seem to lack the dignity of composers of music. This is especially true of jazz, which is almost completely a player’s art, depending, as it does, on improvisation rather than on composition.

This means that the player of jazz is himself the real composer, which gives him a creative and therefore more dignified status.

And then there are those who argue that jazz is loud. Well, so are Souza’s marches and we don’t hear complaints about them. Besides, it’s not always loud, it is very often extremely delicate, in fact. Perhaps this objection stands from the irremediable situation of what’s after all a kind of brass band playing in a room too small for it. But that it is not a fault of jazz itself.

However, the main argument against jazz has always been that it is not art. I think it is art and a very special one. But before we can argue about whether it is or not, we must know what it is. And so, I propose to share with you some of the things I know and love about jazz.

Let’s take that blues we heard before and find out what it is made of …. Now, what are the elements that make that jazz? Well, first of all, there is the element of melody. Western music in general is based, melodically speaking, on scales. Major …, minor … and some others. But there is a special scale for jazz which is a variation of the regular major scale you all practiced as kids …. In jazz, this scale gets modified three different times: the third note gets lowered from this … to this …; the fifth note gets lowered from this … to this …; and the seventh note gets lowered from this … to this … Those three changed notes are referred to as “blue” notes. So instead of a phrase which ordinarily would go something like this …, which is not particularly jazzy, we will get, using blue notes, this phrase … which begins to show a jazz quality.

But this so-called jazz scale is used only melodically. In the harmony underneath, we still use our old unflatter notes, and that causes a dissonance to happen between the tune and the chords …. Do you hear that dissonance? But this very dissonance has the true jazz sounds. Jazz pianists are always using those two dissonant notes together and there is a reason for it. They are really searching for a note that isn’t there at all, but one which lies somewhere between the two notes, between this … and this … And the note is called a “quarter-tone.” The quarter-tone comes straight from Africa, which is the cradle of jazz and where quarter tones are everyday stuff. We can produce one on a wind instrument or a string instrument or with the voice. But on the piano, we have to approximate it by playing together the two notes on each side of it. The real note is somewhere in that crack between them. Well, let’s see if I can sing you a quarter tone, if you will forgive my horrid voice. Here is an African Swahili tune I once heard. The last note of it will be a quarter tone …. Now, that last note .. sounds as if it is certainly out-of-tune but actually it is a real note in another musical language. In jazz it is right at home. Now, just to show how important these so-called blue notes are to jazz, let us hear that same blues played without them, using only the plain white notes of the major scale …. There is something missing, isn’t there? It just isn’t jazz.

But even more important than melody in jazz is the element of rhythm. Rhythm is the first thing you associate with the word jazz, after all. There are two aspects to this point, the first being the beat. The beat is what you hear when the drummer’s foot is beating the bass drum … or when the bass player is plucking his bass … or even when the pianist is kicking the pedal with his foot. All this is elementary. The beat goes on from the beginning to the end of any number, two or four of them to a bar, never changing in tempo or in meter. This is the heartbeat, so to speak, of jazz.

But more involved and more interesting is the rhythm going on over the beat. Rhythmic figures which depend on something called “syncopation,” a word you have certainly heard but maybe were never quite sure of. A good way to understand syncopation might be to think of a heartbeat that goes along steadily and in a moment of shock misses a beat. It is that much of a physical reaction. Technically, syncopation means either the removal of an accent where you expect one or the placing of an accent where you least expect one. In either case, there is the element of surprise and shock. The body responds to this shock either by compensating for the missing accent or by reacting to the unexpected one. Now, where do we expect accents? Always on the first beat of a bar. On the downbeat. If there are two beats in a bar, “one” is going to be strong and “two” is going to be weak. Exactly as in marching. Left, right, left, right, left, right. Even if there are four beats in a bar, it is still like marching, because although we all have only two legs, the sergeant still counts out in four “hup, two, three, four, hup, two, three, four.” There is always that natural accent on “one.” Take it away and there is a simple syncopation …. You see that missing accent on the first beat evokes a body response. Now the other way to make a syncopation is exactly the reverse — putting an accent on a weak beat, the second or the fourth where it does not belong. Like this …. This is what we all do when we listen to jazz, clapping our hands or snapping our fingers on the offbeat …. Now those are the basic facts of syncopation and now we can understand its subtler aspects.

Between one beat and another, there lie shorter and even weaker beats. And when these get accents the shock is correspondingly greater, since the weaker the beat you accentuate, the greater the surprise. Let’s take eight of these fast beats on a bar. One, two, three, four, five, six, seven, eight. The normal accent would fall on “one” and “five” …. Now, instead let’s put a big accent on the real weak one, which is the “four” …. Okay, boys. Thank you.

As you see we got a pure rumba rhythm simply by accentuating the weak fourth beat. Of course, the strongest syncopation of all would obviously be obtained by doing both things at once, putting an accent on a weak beat and taking away the accent from the strong. So now we will do this double operation, put a wallop on the weak fourth beat and remove the strong fifth beat entirely, and we get “one, two, three, four, — , six, seven, eight …. It begins to sound like the “conga,” doesn’t it? But now that you’ve heard what syncopation is like, let’s see what that same blues we heard before would sound like without it. I think you’ll miss that essential element, the very life of jazz …. Sounds square, doesn’t it? Well, that takes care of two very important elements, melody and rhythm.

But jazz would not be jazz without its special tonal colours, the actual sound values you hear. These colours are many but they mostly stem from the quality of the negro singing voice. For instance, when Louis Armstrong plays his trumpet, he is only doing another version of his own voice. Listen to an Armstrong record, like “I can’t give you anything but love” and compare the trumpet solo with the vocal solo. You can’t miss the fact that they are by the same fellow “I can’t give you anything but love, baby. That’s the only thing I’ve plenty of, baby”.[12] Now the trumpet version …. But the negro voice has engendered other imitations too. The saxophone is in itself a kind of imitation of it. Gritty, a little hoarse, with the vibratto or tremor in it ….[13] Just to show you what a vibratto is, let’s hear that sax again without one.[14] Then there are all the different growls and rasps we get by putting mutes on the horns. Here, for example, is the trumpet with a cup mute … and now with the wa-wa mute …; and now listen to a trombone with a plunger mute …. There are other tonal colours that derive from Afro-Cuban sources like the bongo drums …, the maracas …, the Cuban cowbell …, and all the others. Then there are the colours that have an oriental flavour, the vibraphone …,[15] the various cymbals … and so on. All these special colouratiouns make their contribution to the total quality of jazz. You’ve certainly all heard jazz tunes played straight by non-jazz orchestras and wondered what was missing. There certainly is something missing: the colouration. Let’s now hear that same blues sound straight, that is, without any jazz shading at all ….[16] Not the real thing, is it?

There is one more jazz element, one which may surprise some of you who think jazz is not an art. I refer to form. Did you know, for example, that the blues is a classical form? Most people use the word blues to mean any song that is blue or torchy or lowdown or breast-beating like “Stormy Weather,” for example. But “Stormy Weather” is not a blues, and neither is “Moaning Low” or “The Man I Love” or even “The Birth of the Blues.” They are all popular songs.

The blues is basically a strict poetic form combined with music. It is based on a rhymed couplet with the first line repeated. For example, Billie Holliday sings “My man don’t love me treats me awful mean. Oh, he’s the lowest man I’ve ever seen.” But when she sings it, she repeats the first line, so it goes:

“My man don’t love me, treats me awful mean

I said my man don’t love me, treats me awful mean

Oh, he’s the lowest man that I’ve ever seen.”

That is one stanza of blues. A full blues is nothing more than a succession of such stanzas for as long as the singer wishes. Did you notice that the blues couplet is, of all things, in iambic pentameter? … This is about as classic as one can get. It means that you can take any rhymed couplet in iambic pentameter from Shakespeare, for example, and make a perfect “Macbeth Blues”:

“I will not be afraid of death or bane

Till Burnham Forest come to Dunsinam”

It makes a lovely blues ….

Now, if you’ve been very attentive, you’ve noticed that each of those three lines, we’ve got four bars apiece, making it all a twelve bar stanza. But the voice itself sang only about half of each four-bar line … and the rest was filled up by the orchestra. This filling up is called a break. And here in the break we have the origin of the instrument imitating the voice, the very soil in which jazz grows.

Perhaps the essential sound of jazz is Louis Armstrong improvising the breaks in the blues sung by Bessie Smith. From this kind of voice imitation, all instrumental improvising has since developed. Listen to that sound:

My Mamma says I’m reckless, but Daddy says I’m wild.

My Mamma says I’m reckless, but Daddy says I’m wild.

I ain’t good lookin’ but I’m somebody’s angel child.

Did you notice the instrument that is accompanying the singer? It is a harmonium, that wheezy little excuse for an organ which we all associate with hymn tunes. But far from being out of place in the blues, this instrument is especially appropriate, since the chords in the blues must always be exactly the same three chords we all know from hymn tunes. … These chords must always remain in a strict classical pattern, pure and simple. Try to vary them and the blues quality flies out the window.

Well, there you have it. Melody, rhythm, tone, color, form, harmony. In each department there are special features that make jazz instead of just music. Let’s now put them all together and hear a full blown, all out, happy blues. Oh, did you know that blues could be happy? Just listen. …[17]

By this time I’ve probably given you the impression that jazz is nothing but blues. Not at all. I’ve only used the blues to investigate jazz because it embodies the various elements of jazz in so clear and pure a way. But the rest of jazz is concerned with applying the same elements to something called the “popular song.”

The popular song too is a form, and has certain strict patterns. Popular songs are in either two-part or three-part forms. By far the most numerous are in the three-part. You all know this form, of course, by hearing it so much. It is simple as pie. Anyone can write one.

Take “Sweet Sue”, for instance. All you need really is the first eight bars, which in the trade are called the front strain. … Now the song is practically written, since the whole thing will be only thirty-two bars long, four groups of eight bars apiece. Now the second eight is the same exactly as the first …, making sixteen bars and we’re already half finished. Now the next eight bars, which are called “the release,” or “the bridge,” or just simply “the middle part.” This must be different music but it doesn’t matter if it’s very good or not, since most people don’t remember it too well anyway … and then the same old “front strain” all over again … and it’s finished. Thirty-two bars and a classic forever. Easy, isn’t it?

But “Sweet Sue” is still not jazz. A popular song doesn’t become jazz until it is improvised on. And there you have the real core of all jazz: improvisation.

Remember I said that jazz was a player’s art rather than a composers? Well, this is the key to the whole problem. It is the player who, by improvising, makes jazz. He uses the popular song as a kind of dummy to hang his notes on. He dresses it up in his own way and it comes out an original. So, the pop tune in acquiring a new dress, changes its personality completely like many people who behave one way in blue jeans and in a wholly different way in dinner clothes. Some of you may object to this dressing up, you who say, “let me hear the melody and not all this embroidery.” But until you accept this principle of improvisation, you will never accept or understand jazz itself.

What does improvising mean? It means that you take a tune, keep it in mind with its harmony and all and then, as they used to say, just “go to town” or “make it up” as you go along. You “go to town” by adding ornaments and figurations or by making real old-fashioned variations just as Mozart and Beethoven did.

Let me show you a little how Mozart did it and then you may understand better how Erroll Gardner does it. Mozart took a well-known nursery rhyme which he knew as “A vous dirais-je, maman” and which we know as “Twinkle, twinkle little star” or as a way of singing the alphabet: A, B, C, D, E, F, G, H, I, J and so on.

Now, Mozart makes a series of variations on this tune. One of them begins …, then another … and another one begins … and yet another …. They are all different pieces, yet they are all in one way or another that same tune ….

The jazz musician does exactly the same thing. There are infinite possible versions of “Sweet Sue,” for example. The clarinet player might improvise one chorus of it this way …. Now he could have done that in any number of ways and if I asked him to do it again tomorrow morning it would come out a whole other piece, but it would still be “Sweet Sue” and it would still be jazz. In fact, let’s ask kim to try it again and see how different it is ….

Now we come to the most exciting part of jazz, for me at any rate, simultaneous improvising. This happens when two or more musicians improvise on the same tune at the same time. Neither one knows exactly what the other is going to do but they listen to each other and pick up phrases from each other, sort of talk together. What ties them together is the chords, the harmony of “Sweet Sue.” Over this harmony they play two different melodic lines at the same time, which in musical terms makes a kind of accidental counterpoint. This is the germ of what is called the “jam session.” Now the trumpet is going to join with the clarinet in a double improvisation on “Sweet Sue” and see if you can distinguish the two melodic lines …. The business of improvising together gave rise to the style called “Dixieland,” which is constantly having a big revival. One of the most exhilarating sounds in all music is that of a Dixieland band letting out its final chorus, all stops out, with everyone improvising together.

Here is that Dixieland chorus of “Sweet Sue” …. You see how exciting this can be?

But jazz is not all improvisation, not by a long shot. Much of it gets written down and it is then called an arrangement. The great days of arrangements were the thirties when big startling swing arrangements were showing off the virtuosity of the great bands like Casanova, Benny Goodman, Artie Shaw, the Dorsey Brothers, and so on.

Now jazz is hard to write down. There is no way of notating exactly those quarter tones we talked about, nor the various sneers and growls and subtle intonations. Even the rhythms can only be approximated in notation. So that much of the jazz quality is left to the instincts of the player who is reading the music. Still, it does work because the instincts of those players are so deep and genuine. Let’s listen to a good solid swing arrangement of the chorus of “Sweet Sue” as we might have heard it back in 1938 ….[18]

Now, remember this arrangement was for dancing. In 1938 we were all dancing and that brings out the most important point of all. Nobody seems to dance the jazz very much anymore except for mambo lovers, and they are limited to those who are athletic enough to do it.

What has happened to dancing? We used to have a new dance practically every month. The Lindy Hop, the Shag, the Peabody, the Big Apple, Boogie, Suzycue; now we have only dances you have to take lessons to do. What does this mean? Simply that the emphasis is on listening these days, instead of on singing and dancing. This change had to happen. For one thing, the tremendous development of the recording industry has taught us to listen in a way we never did before. But even more important with the advent of more complicated jazz like swing and boogie-woogie and bop, our interest has shifted to the music itself, and to the virtuosity of its performers, that is, we are interested in what notes are being played, how well, how fast and with what originality. You can’t listen to bop intelligently and dance too, murmuring sweet nothings into your partner’s ear. You have to listen as hard as you can to hear what’s happening. So, in a way, jazz has begun to be a kind of chamber music, an advanced, sophisticated art, mainly for listening, full of influences of Bartok and Stravinsky and very, very serious.

Let’s listen, for a moment, to this kind of arrangement of our old friend, “Sweet Sue.” …[19]

Now, whether you call this weird piece cool or crazy or futuristic or modernistic or whatever, the fact is that it is bordering on serious concert music. The arrangement begins to be a composition. Take away the beat and you might not even know it’s jazz at all. In fact, let’s hear a little of it, without the beat and see ….

What we are hearing might perfectly well be a concert piece. Why is it jazz? Because it is played by jazzmen on jazz instruments and because it has its roots in the soil of jazz and not of Bach. I think the key word to all this is the word “cool.” It means what it implies. Jazz used to advertise itself as “hot,” now the heat is off. The jazz player has become a highly serious person. He may even be an intellectual. He tends to wear Ivy League clothes, have a crewcut or wear hornrimmed glasses. He may have studied music at the conservatory or university. This was unthinkable in the old days. Our new jazz man plays more quietly, with greater concentration on musical values, on tone quality, technique. He knows Bartok and Stravinsky and his music shows it. He tends to avoid big, flashy endings. The music just stops when it is over. As he has become cool, so have his listeners; they don’t dance, they listen respectfully as if to chamber music and applaud politely at the end. At jazz night-clubs all over the world, you find audiences who do not necessarily have a drink in their hands and who do not beat out the rhythm and carry on as we did when I was a boy.

It is all rather cool and surprisingly controlled, considering that jazz is essentially an emotional experience. Where does this lead us in our investigation? To some pretty startling conclusions. There are those who conclude from all this that here in the new jazz is the real beginning of serious American music, that at last the American composer has his own expression. Of course, when they say this, they are intimating that all American symphonic works up to now are nothing but personalized imitations of the European symphonic tradition from Mozart to Mahler.

Sometimes I must say I think they have a point. At any rate, we can be sure of one thing: that a line between serious music and jazz grows less and less clear. We have serious composers writing in the jazz idiom and we have jazz musicians becoming serious composers. Perhaps we have stumbled on a theory. But theory or no theory, jazz goes on finding new paths, sometimes reviving old styles, but in either case looking for freshness.

In any art that is really vital and searching splits are bound to develop, arguments arise and faction’s form. Just as in painting, the non-objectivists are at sorts point with the representationalists and in poetry the imagists declaim against the surrealists. So, in jazz music we have a major battle between the traditionalists and the progressives. These latter are the ones who are trying hardest to get away from the patterns of half a century, experimenting with new sonorities, using note relationships that are not common to the old jazz and in general trying to keep jazz alive and interesting by broadening its scope.

Let us see if we can feel the essential difference between the two schools by listening to a progressive session on — you guessed it — “Sweet Sue.” This style will embody all the elements we have discussed as distinguishing jazz from all other music but will use them in a new and different way…[20]

Well, we’ve heard jazz as it comes from the past, and we’ve had a sample of what might turn out to be the future of jazz. What we’re hearing now is jazz in the present tense, still a fresh, and vital art with a solid past and an exciting future.

[2] Leadbelly, New Black Snake Moan.

[3] The Rampart Street Paraders

[4] Turk Murphy, Maple Leaf Rag.

[5] Buck Clayton, Christopher Columbus.

[6] Pete Johnsosn, Boogie-Woogie.

[7] Phil Woods, sax, Bob Prince, Stutters.

[8] The Don Butterfield Sextet, Bob Roberts, Canzonetta.

[9] Machito, Freezeland.

[10] Bessie Smith, Empty Bed Blues.

[11] Seguem-se exemplos com uma banda especialmente reunida por Buck Clayton: Lawrence Brown, trombone, Buster Bailey, clarinete, Coleman Hawkins, sax tenor, Freddie Green, guitarra, Eddie Jones, baixo, Gus Johnson, bateria, Leonard Bernstein, piano.

[12] Louis Armstrong, I Can’t Give You Anything but Love, Baby.

[13] Coleman Hawkins

[14] Coleman não conseguiu tocar sem o vivratto. Morreu de rir, tentando, no fim chamaram Romeo Penque para tocar quadrado.

[15] Bob Prince

[16] Sherry Ostrus

[17] Happy Blues, Nat Pierce, piano.

[18] Boyd Raeburn Orchestra

[19] Don Butterfield Sextet, arranjo Teo Macero, também sax.

[20] The Miles Davis Quartet, introdução num arranjo de Teo Macero.



Flavio Musa de Freitas Guimarães

Already watching the eighty-eight turn of the Earth in curtsy around its King, I’m an engineer that became a writer, happy, in perfect health, body and mind.