The argument between my pals a few days ago made me think: 'Wow! I have been writing a blog called Enjoying Traditional Jazz for several months. Do I really know what I'm talking about?'
The kind of music I am writing about encompasses all the following terms (and probably more):
New Orleans Jazz
West Coast Jazz
Jug Band Music
In other words, for me traditional jazz is about a style of playing: a group of musicians take a tune and agree the key, the melody and the chord sequence and away they go, playing the material and improvising around it. Generally there is a fixed tempo and generally the 'choruses' are repeated end-to-end as many times as required. There may or may not be an agreed musical arrangement - either a 'head' arrangement or one on paper. The tunes are drawn largely but not exclusively from the repertoires of the classic jazz bands from the first half of the Twentieth Century and popular music generally.
I do not have a fixed idea about what instruments a traditional jazz band should contain and I do not agree that a traditional jazz band must have six or seven players. I think traditional jazz can be played by any number of players - from one to perhaps as many as ten (provided they do not tread on each other's toes).
I do not even believe that a trad band should have a 'front line' of trumpet, clarinet and trombone and a 'rhythm section' of bass (tuba or string), drums and chord instrument (guitar, banjo or piano). Although this formation has worked well for many bands for decades, I think traditional jazz being played by bands that include a violin, a washboard, a harmonica or whatever is just as valid. Look at photos from the bands of the 1920s: there are various combinations of instruments and you often find the leader was a violinist.
What I do not count as traditional jazz is 'free jazz'. And 'modern jazz' is not quite traditional jazz either, though there is more overlap with traditional jazz than some may think.
Do the musicians have to be black in order to achieve greatness? Well, certainly when you listen to such a player as Johnny Dodds, you understand why some theorists think so. But white musicians have contributed massively to the history of traditional jazz, in composing and performing. And now we have the new generation of young musicians who have gravitated to the streets of New Orleans. Most of them are white; and they play with great technique and feeling. Their music - for me - is traditional jazz. You can find plenty of it on YouTube. Try any of these bands:
The Palmetto Bug Stompers
The Gentilly Stompers
The Shotgun Jazz Band
The Smoking Time Jazz Band
The Little Big Horns