John Jackson, 77, one of the last masters of the so-called Piedmont-style blues singing and guitar picking, who was recognized in 1986 as a National Heritage Fellow by the National Endowment for the Arts, died of kidney failure Jan. 20 at his home in Fairfax Station. He had liver and lung cancer.

Mr. Jackson never completed first grade while growing up in rural Rappahannock County, Va. But he learned a library's worth of music by ear and recorded nine albums from 1965 to 1999.

His emergence as a performer coincided with a movement to preserve the unwritten repertoire of Delta and Piedmont blues songs, which had long been played by gifted itinerant or uneducated musicians.

"I don't read and write, and I have to keep everything right up there," Mr. Jackson once told The Washington Post, pointing to his head.

Mr. Jackson sang for presidents and audiences around the world, from local coffeehouses to Carnegie Hall in New York and the Royal Albert Hall in London. The State Department sent him on tours abroad to represent the finest in American music.

He was awarded a National Heritage Fellowship, the country's highest recognition in the folk and traditional arts, four years after it was first created.

Washington Post critic Geoffrey Himes was impressed with Mr. Jackson's mastery on his final release, "Front Porch Blues" (Alligator Records). "Like many an older artist," Himes wrote, "Jackson has pared away all the unnecessary notes to reveal the essential dialogue between his gravelly baritone voice and his sparkling, skeletal guitar lines."

For all his acclaim, Mr. Jackson continued to work as a part-time gravedigger in Fairfax and Prince William counties, and never saw music as a full-time occupation. He might share a bill with Pete Seeger and the Carter Family one weekend and return to the graveyard on Monday. In recent years, he had begun training others in grave-digging.

"It may be hard work to some people," he told The Post. "I grew up with hard work, and it really don't bother me at all. All you have to do is cut the [grave] ends at first and dig straight down. . . . There's nothing nicer than getting up in the morning and having breakfast and getting out to do some work."

Mr. Jackson grew up on a Woodville farm, the seventh of 14 children. His parents were amateur musicians, but he credited a chain gang convict he knew only as "Happy" with his earliest guitar training.

The two met, Mr. Jackson said, when the convicts were laying a blacktop road and wanted water from the Jackson farm for refreshment. In return for the water, Happy showed the young man the essentials of fingerpicking blues.

Listening to the Grand Ole Opry by radio and the family's collection of blues, jazz and gospel records also helped Mr. Jackson learn the instrument.

As he grew older, Mr. Jackson was invited to play at local gatherings but spent most of his time as a handyman and performing odd jobs. A violent fight at one country party, at which a man accused Mr. Jackson of stealing his guitar, turned him off to music for years, as did an increased demand for rock-and-roll.

Hoping for a better life for himself and his family, he moved to Fairfax County in 1949 to work on a dairy farm. He also became caretaker of Fairfax City Cemetery.

He said he had long forsaken his musical ambitions when a bunch of bored children wandered by one day and asked Mr. Jackson to entertain them with a song. Soon he was giving lessons in the back room of a local Amoco station.

Charles L. Perdue, a government employee who had just helped start the Folklore Society of Greater Washington, stopped at the Amoco one day in 1964 and saw Mr. Jackson with the guitar.

Perdue, now a professor of folklore at the University of Virginia, recalled yesterday that when he asked Mr. Jackson to play some songs, he demurred. "I only hit a couple of chords," Mr. Jackson told him shyly.

He coaxed Mr. Jackson to play Mississippi John Hurt's "Candy Man" and was immediately struck by his precise rendering of the complex piece. Perdue persuaded Mr. Jackson to play at the old Ontario Place in Washington, where record label officials often caught top local acts.

Chris Strachwitz, whose California-based Arhoolie label became a force in roots music, caught one of Mr. Jackson's performances and decided to record him. They went to Mr. Jackson's home, taped him for 11 hours and paid him $150. A year later, "Blues and Country Dance Songs From Virginia" came out. Mr. Jackson said he never made enough money from his songs to quit grave-digging.

Mr. Jackson's wife, Cora Lee Carter Jackson, died in 1990. Three sons, Ned Jackson, Macarthur Jackson and John Jackson Jr., also predeceased him.

John Jr., a janitor at the Talent House School in Fairfax, was shot to death in 1978 by Fairfax County police when officers mistook him for a burglar.

Survivors include three sons, Lee F. Jackson of Manassas, Timothy Jackson of Alexandria and James Jackson of Fairfax Station; a daughter, Beth Johnson of Fairfax Station; a sister, Roberta Wigington of Vienna; two brothers, Thomas Jackson of Landover and Fred Jackson of Rappahannock County; seven grandchildren; and five great-grandchildren.

Guitarist John Jackson was named a National Heritage Fellow by the National Endowment for the Arts. Despite fame, he continued to work as a gravedigger.