Alas. Most good things eventually come to an end. And, here's yet another: The famed Tokyo String Quartet will give its last Bay Area concert at April 18 at Herbst Theatre in San Francisco. It's bound to be a rare and singular event, one that aficionados of superlative music-making won't want to miss.

The TSQ's current members are Martin Beaver and Kikuei Ikeda, violins; Kazuhide Isomura, viola; and Clive Greensmith, cello. The planned program will be Mozart's Quartet in D major, K. 499, the "Hoffmeister"; Russian-American composer Lera Auerbach's "Farewell" Quartet, which was written for TSQ; and Brahms' Quartet in C minor, Op. 51, No. 1.

The instruments the musicians play are unique, and they have a title of their own: the "Paganini Quartet." All four are renowned Stradivarius instruments named for Nicolo Paganini, the legendary virtuoso who acquired them during his 19th-century career. They were purchased from the Corcoran Gallery of Art in Washington, D.C., by the Nippon Music Foundation and have been on loan to the Toyko Quartet since 1995.

The Herbst concert is part of the venerable 44-year-old-year old ensemble's 2012-2013 final season, during which it is performing "farewell" concerts throughout Europe, North America, Japan, New Zealand, Australia and more. Their very last performance is scheduled for June 15 in Wellington, New Zealand.

Tokyo beginnings

While the quartet was officially founded at the Juilliard School of Music in New York City in 1969, the idea for its formation germinated in Tokyo's Toho School of Music. Its original four members were violist Isomura, Koichiro Harada, Yoshiko Nakura and Sadao Harada. It was Toho professor Hideo Saito to whom the four founding members gave credit for instilling in them a deep commitment to chamber music.

After coming to the United States for further study, it was a case of "veni, vidi, vici" for the young quartet: First, the ensemble won the first prize at the Coleman Competition, then the Munich Competition and the Young Concert Artists International Auditions. Following right on the heels of these international awards, Deutsche Grammophon signed them to an exclusive contract, thus launching them on their path to more than 40 years of fame and acclaim.

Of course, there have been some changes along the way. In 1981, Peter Oundjian assumed the first violin position, followed by Andrew Dawes in 1995, Mikhail Kopelman in 1996 and Beaver, from 2002 to the present. Nakura had only one successor as second violin: Ikeda in 1974. Isomura, of course, has held the viola position for the quartet's entire lifetime, and Greensmith remains the single replacement for original cellist Harada, beginning in 2000.

But, why does such an extravagantly lauded, world-famous group decide to cease to be?

'A graceful close'

According to first violinist Beaver, there was no shortage of fine applicants eager to audition for the viola and second violinist positions following Ikeda and Isomura's retirement announcement back in 2011. But, Beaver explained, rather than continuing with two new members, they came to a mutual decision that the most fitting way to honor and celebrate the quartet's long and illustrious career "was to bring it to a graceful close." In an email exchange while the quartet members were on a train to Boston, I asked them to describe a special highlight or two from their TSQ years.

Violist Isomura responded: "There is one highlight that stands out to me. The Tokyo String Quartet played the entire Beethoven cycle (of string quartets) on six consecutive nights in Milan at the La Scala Opera House. On the final night we did well and got a big ovation. For an encore, we decided to play 'Cavatina,' the fifth movement from Op. 130. When we finished playing, nobody moved, nobody clapped; it was dead silent for something like 15 seconds -- an unbelievable silence. Then the audience gradually began to clap, and the clapping went on for a long time. I couldn't believe it -- I was simply so touched -- the way they responded, the special ambience there. I had tears in my eyes, which was the first time that had ever happened to me onstage. I was shy about it and tried to hide it. I looked at my colleagues, and they all had tears in their eyes, and when I looked at the audience in the front row, they had tears in their eyes, too. That was the experience of my lifetime!"

Cellist Greensmith described his memorable moment as "performing in the Teatro Ponchielli, in Cremona, the spiritual home of Italian violin-making and birthplace of Stradivari."

Details: 8 p.m. April 18, 401 Van Ness Ave., San Francisco; $36 and $48; 415-392-4400, www.cityboxoffice.com.

UP POPS PIPPIN: Even if you think you hate opera, you owe it to yourself to have some fun and even a few belly laughs by taking in a performance of Donald Pippin's inimitable Pocket Opera. Fortunately, Pocket Opera will be presenting Jacques Offenbach's "Orpheus in the Underworld" April 14 at the Palace of the Legion of Honor in San Francisco. Just to give you an idea of what's in store, here's a line from Maestro Pippin himself: "Pocket Opera returns to the Legion after a two-year exile, offering another breath of fresh arias." While libretto frivolity is likely, the musical quality will be excellent. Details: 2 p.m., 34th Avenue and Clement; $15-$39; 415-972-8934.

LOOKING EASTWARD: "Notes From the Middle East" is the title of the Oakland East Bay Symphony's next concert April 20 at the Paramount Theatre. Michael Morgan and Daniel Wachs will share conducting duties, and Eliran Avni will be piano soloist. The program will include the Grieg Piano Concerto, "Ya Way Li" by John Basharat, "Astrolatry" by Avner Dorman, "The Nile Bride" by Nader Abbassi and more. Details: 8 p.m., 2025 Broadway, Oakland; $20-$70; 800-745-3000, www.oebs.org.

Contact Cheryl North at cherylnorth@hotmail.com.

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To hear the Tokyo String Quartet play the Cavatina movement from Beethoven's String Quartet in B-flat major, Opus 130, go to www.mercurynews.com/music.