John Jackson, a rural Virginian, does not play rock 'n' roll. He'll tell you that right off. ''I don't fool around with disco or soul,'' he says affably, in a deep drawl that carries the last word of his sentences into several more syllables.
What he does play is the blues - Delta blues, like those of his friend Mississippi John Hurt, and the finger-picking East Coast of Piedmont blues, a country-style music plucked out with nine fingers that is considered one of the most difficult of America's originals to play.
The playing seems to go on almost ceaselessly in his bright blue living room, whose walls embrace a jumble of family photographs and old black-and-white portraits of Robert E. Lee and his generals. ''We get a lot of guitars and banjos through here,'' says Mr. Jackson, sitting in a rocking chair with his hands folded awkwardly across his denim overalls. ''Would you like me to play you a song?''
A musician and not a talker, Mr. Jackson is clearly more comfortable with his guitar in hand. Though he'll answer any question you'd care to put to him with a politeness bred in Virginia, he looks a little itchy without his instrument.
He learned to play it, he says, not from his daddy, ''though my father did play the guitar and ukelele. He was left-handed, and he used to play the guitar upside-down. I couldn't learn nothing off him,'' he explains.
Instead, he picked up the basics from a convict named Happy, who worked on a chain gang near Mr. Jackson's farm in Rappahannock County, Va., laying hardtop road. ''He come down to my family's spring to haul water each day,'' Mr. Jackson explains, ''and he asks me what kinds of things we did for fun around here. So I told him we played ball and marbles and did music.
''He asked what kind of instruments we played, so I told him about my father, '' he continues, ''and my mother playing accordion and harmonica. He told me if I went and fetched my father's guitar, he'd play me a song the next time he came.''
The convict - ''we never did know his last name'' - came and taught the youngster a bit each day, until after six months, the warden trusted Happy to go to the Jackson home each evening and play until 9. ''He was just like his name, '' Mr. Jackson says. ''He was the happiest man I ever did know - never moaning or fussing, always a song.''
After a year of work, Happy was set free, and the Jacksons took him in for a few days. ''Then we walked him down to hop the mail train, and he said he'd be back in a few days. Haven't seen him since,'' he says.
That experience taught Mr. Jackson to play, but old 78 rpm records taught him his repertoire of ''six, seven, maybe 800 songs. And they're all upstairs - I can't read nor write, so I keeps them up there,'' he says, pointing to his straight black hair.
The 78s came from a pair of furniture dealers who dropped by the house one day. ''They wanted to sell us a music box. My father said we had no money for such foolishness and went back to work,'' Mr. Jackson says, ''and the furniture dealers went up on the hill to eat their lunch. Pretty soon, here they come back with a record playing on the record player, and my mother coming out of the house, wanting to know where that music come from.''
They made the sale and returned each month ''to collect a little on it, and sell us a few more records for 10 cents a piece. We bought everything - Bessie Smith, the Carter family, all the old greats.''
Young John Jackson then cut himself a ''rubber band out of an old tire, and hooked it onto a stick to use as a capo'' (used to move the scale up or down), and then ''stood in back of the record player and played along. That's how I learned the most,'' he says.
He started playing professionally for schools, fairs, clubs, and field days when he was 12, playing along with one of his 13 brothers and sisters or by himself.
And he kept playing at clubs when he moved to Fairfax as a young man to work on a dairy farm, but stopped because ''I couldn't stand the violence. There'd be all these people drinking in these clubs, and I never did hold with fighting - never had a fight with anyone in my life - so I just had to quit.''
Then he met some people working a construction crew who were looking for a place to play and wound up ''fooling around'' with them on his front porch ''pretty near every weekend.'' When they got laid off, he says, they ''came to the house where I was working - the lady who owned the dairy farm asked me to be caretaker one day and wouldn't let me go after that - and asked if I'd give them
He borrowed the $50 from his boss, and, not hearing from his friends, has used that steel-string Gibson ever since. ''I call it Standby,'' he says. Why is that? ''Well, I guess it's stood by me all these years.''
He looks at the polished instrument, thinking of another song by one of his friends - Skip James, Sunhouse, Blind Lemon Jefferson. He plays the songs, which seem to start up by themselves, along with his son James - the youngest of seven children, an auto-body worker and guitarist with a mustache and a T-shirt who calls his dad his ''No. 1 hero.''
The hero recently came out with his fifth album (''Deep in the Bottom,'' Rounder Records) and talks of a quirky string of events that led to recording his first. ''I was sitting on the front porch playing a song,'' he says, warming to this oft-told story, ''and the mailman came up and heard us playing. Well, he wouldn't leave me alone until I promised to come down to the Amoco station where he worked nights to teach him some things.''
Mr. Jackson held to his promise, and was playing Mississippi John Hurt's ''Candy Man'' when a man came in to get some gas and wanted to know what he was playing. ''I said, 'Nothing.' He said, 'Come on, what are you playing? Play it again.' So I told him it was Candy Man and played it. Then he asked me what else I could play. Nothing. And he wouldn't leave me alone until I played him a few more songs.''
The man - Shep Perdue of the Washington Folklore Society - asked him if he wanted to go see John Hurt in person at a concert the next week, but Mr. Jackson replied, ''That man ain't alive.'' But Mr. Perdue came by the next Friday to take him to the concert, ''and I wasn't ready, I thought he was fooling.''
He went to meet the famous blues guitarist, and found that ''we had a lot in common - he was raised on a farm, same as me. We got to be good friends, sitting on the porch and talking about working mules and all - real country talk. He was a right nice man; I was very fond of him.''
The next week, Mr. Jackson went with Mr. Perdue again, this time to meet blues guitarist Lance Lipscomb. He was invited on stage to play a couple of songs, but halfway through the first, ''a fellow jumped up from the audience and said he was from a record company and would like to record me. And I've been going ever since,'' he says.
With recording companies and the State Department, Mr. Jackson has traveled to Europe, to the Caribbean, and on one world tour, playing to audiences that are more receptive than Americans. ''The average 10-year-old on the street in Europe asks you a question about the blues, you'd better give him the straight answer, because he knows all about it,'' he says.
He's found his music to be a great communicator to those in other nations. ''A man don't understand you, but you pick up your guitar and play a little lick , and he knows just what you mean,'' he says, breaking into a ragtime that James converts into rock 'n' roll.
James is the surviving son, Mr. Jackson says. ''One of my boys went to Vietnam and got some kind of illness, and another one was working late at the school where he had a job, setting up something for the next morning. The Fairfax police thought he was a burglar and shot him.'' Mr. Jackson rocks, hands on Standby. ''Well, you just got to live with it,'' he says.
''I think music is the happiest thing,'' he said. ''When you feel down and out, you can pick yourself up again. I'd be happy to play another song.''