It would have been a heart-stopping moment for any violinist. Midway through the last movement of Leonard Bernstein’s wildly difficult “Serenade” — with Bernstein himself conducting the orchestra — the tiny, doll-like soloist Midori suddenly felt the E string on her violin snap. She calmly turned to the concertmaster, who handed her his own instrument (which was much larger than hers), and she picked up where she had left off — until the E string on that violin snapped as well. Midori didn’t miss a beat. She turned back to the concertmaster to borrow a second violin and finished the piece flawlessly.

The crowd at the Tanglewood Music Festival exploded to its feet, and Bernstein swept her up in a tearful hug as the orchestra broke out in cheers. The headline in the New York Times the next day summed it up: “Girl, 14, conquers Tanglewood with 3 violins.”

Since that remarkable evening in 1986, Midori — perhaps the most celebrated child prodigy of modern times — has become one of the world’s most sought-after violinists, and her appearances on March 31 and April 1 with the Alexandria Symphony Orchestra, performing Mendelssohn’s Violin Concerto (which she calls “one of the most beautiful pieces ever written”), will be a key violin event of the season.

But Midori won’t be spending the coming week in rehearsals. Instead, she’ll be in high school classrooms around Alexandria and Arlington, helping young musicians prepare for their own performances with the ASO. It’s part of her Orchestra Residencies Program, one of several programs that the virtuoso has established to support young players and youth orchestras — and that reflect, she says, her driving purpose in life.

“I am passionate about education and music education in particular,” says the violinist, now 40 and — for someone who had to endure being labeled a “miracle” at the tender age of 10 — refreshingly down to earth. Performing still takes up the bulk of her time, she says; she gives between 90 and 100 concerts a year, often with other superstars of the classical world, and she practices at least several hours a day.

Midori. (Timothy Greenfield-Sanders/Courtesy of Opus 3 Artists)

But over the past several decades, Midori has been making an impressive impact as a teacher and a philanthropist as well. She heads the string department at the University of Southern California’s Thornton School of Music, and in addition to the Orchestra Residencies Program, she’s launched Partners in Performance to promote chamber music in underserved areas; the Japan-based Music Sharing program; and Midori & Friends, which underwrites music education in New York City.

“She’s devoted to the cultivation of young talent,” says Kim Allen Kluge, who is music director of the Alexandria Symphony and whose new work, “Meibuki,” will be premiered by the orchestra with students under Midori’s coaching. “And she’s an exquisitely refined player. Working with someone who is so exacting will be an unforgettable experience for the young musicians.”

Midori’s intense involvement with children may not be surprising, given her strange and all-too-brief childhood. Born in Japan in 1971 as Midori Goto (she dropped her last name when her parents divorced), she had a talent that was quickly noticed by her violinist mother, who gave the child a tiny violin on her third birthday. Her progress was spectacular by any standard; she gave her first recital at 6, and two years later a recording of her playing found its way to Dorothy DeLay, perhaps the leading violin teacher in the world. DeLay, impressed, invited the girl in 1981 to come to the United States to perform at the prestigious Aspen Summer Music Festival.

Her childhood would never be the same. Arriving at Aspen with a stuffed animal under her arm, Midori played Bela Bartok’s fiendishly difficult and emotionally complex Second Violin Concerto, astonishing the audience and even bringing some to tears. She played “like only a few people in the universe can do at any time,” violinist Pinchas Zuckerman said then. “I’ve just witnessed a miracle.”

With the spotlight suddenly on her, Midori’s life shifted into high gear. Her mother divorced and — though she had no money, and neither of them spoke English — moved to New York the next year so the girl could begin studies with DeLay. Midori mastered the repertoire with uncanny speed, began concertizing and at 16 became a full-time professional, squeezing in schoolwork between performances and daily seven-hour practice sessions.

But the strains, inevitably, began to show. Prodigies face unthinkable pressures, from expectations about their careers to living out the public personas that their managers construct for them. In 1987, Midori rebelled. She unexpectedly quit her mentor DeLay under emotional circumstances (her mother had become involved with one of DeLay’s associates, a man who later became her stepfather) and took charge of her own career. Observers noted that she seemed to be subsisting on salads and thin air, and at her Carnegie Hall debut two years later, she weighed about 90 pounds — worrying even for someone who is only 4-foot-11.

Then, in September 1994, she suddenly canceled her concerts and withdrew completely from public view.

Rumors flew. It was reported that she had a “digestive disorder,” but talk was rife of a mental breakdown, of crushing pressure from a controlling mother, of incessant demands from her management. The truth, as she admitted in an interview a decade later, was that she was deep in the kind of medical crisis often found in stressed-out perfectionists. “I was severely anorexic,” she told the Toronto Globe and Mail. “That wasn’t my only experience in the hospital — but it was the longest, and that was the first time I was given the official diagnosis.”

The crisis passed and may have marked a turning point. As an adult in her 20s, freed of the burden of being a prodigy, Midori seemed finally able to forge a more normal life. While continuing to perform, she enrolled in New York University to study psychology — for a while she considered it as an alternative career — and began what she calls her “mission” of working with children.

“Going through the transition to become an adult master has informed her passion for helping young people,” says the ASO’s Kluge.

But for Midori herself, the issue is less complex.

“I’m happy,” she says simply, “when I’m surrounded by my students.”

Midori will perform Mendelssohn’s Violin Concerto with the Alexandria Symphony Orchestra on March 31 and April 1 at the Rachel M. Schlesinger Concert Hall and Arts Center, 3001 N. Beauregard St., Alexandria. Also on the program will be the world premiere of “Meibuki,” a work by ASO music director Kim Allen Kluge. Contact the box office at 703- 548-0885 or go online for tickets.