The classical music world loves a good birthday party, and this year, there’s good reason to throw some major ones: the bicentennials of Giuseppe Verdi and Richard Wagner, and the centennial of Benjamin Britten.

Sometimes, though, it’s enough to just celebrate without the excuse of a big birthday or anniversary. This season, pianist Emanuel Ax will salute Brahms, whose bicentennial birthday doesn’t roll around until 2033, with a set of three chamber concerts. Called the Brahms Project, the series is sponsored by the Chicago Symphony Orchestra Association’s Symphony Center Presents, the Los Angeles Philharmonic, Carnegie Hall and Cal Performances at the University of California at Berkeley.

In Chicago, the series begins Jan. 26 with Ax and mezzo-soprano Anne Sofie von Otter performing works by Brahms and a world premiere of three songs by young American composer Nico Muhly. The series continues Feb. 21 with Ax and Yo-Yo Ma, the CSO’s Judson and Joyce Green Creative Consultant, in Brahms’ two cello sonatas and a new work for cello and piano by Swedish composer Anders Hillborg. The project closes May 18 with a solo piano recital featuring Ax in two Brahms works and two new solo pieces by Australian composer Brett Dean and New York City-based composer Missy Mazzoli.

Why Brahms? Why this year? Ironically, the project grew out of Ax’s celebration of the 200th birthdays of Chopin and Robert Schumann in 2010.

“For Chopin and Schumann’s birthdays, I did three programs,” Ax said. “It was the same idea: Dawn Upshaw in one program, Yo-Yo in another and then a recital. Also we commissioned composers for that project.”

Ax presented the programs in several locations, including New York City and the West Coast. “The L.A. Philharmonic was happy with the concept, and the artistic administrator there asked if I would like to do another one along those lines.”

They came up with a focus on Brahms, even though no big anniversaries were pending for the composer. “I’m a Brahms fanatic,” Ax said. “When I was growing up, at age 14 or so, I fell completely in love with the Second Piano Concerto. I absolutely wore out two LPs of it, I loved it so much. Why Brahms? How can you explain what you’re in love with? Certainly it’s obvious that he’s one of the great, great composers. But why particularly? That’s hard to explain. That’s one of the nice things about music; you can’t put it into words.”

In addition to the two Brahms cello sonatas on Feb. 21, the series will showcase von Otter in Brahms’ Four Serious Songs, along with other Brahms songs, and Ax playing assorted Brahms piano works on Jan. 26. The major Brahms works on Ax’s solo recital in May will be the Variations and Fugue on a Theme by Handel and the Second Piano Sonata.

Ax believes that commissioning works from four contemporary composers is especially appropriate for the Brahms Project. One of Brahms’ best friends was the legendary violin virtuoso Joseph Joachim, whose motto was “Frei aber einsam” (“Free but lonely”). In 1853, Brahms and friends Robert Schumann and Albert Dietrich collaborated on a new work for Joachim that became known as the “F-A-E” Violin Sonata because it incorporated those three notes in various combinations.

As the story goes, Brahms, echoing Joachim, created his own personal motto, “Frei aber froh” (“Free but happy”). (That three-note F-A-F motif is noticeably present in Brahms’ Third Symphony.) Ax suggested that Muhly, Mazzoli, Dean and Hillborg keep the F-A-F idea in mind when composing their pieces for the Brahms Project.

Whether we’ll be hearing assorted versions of those three notes in all four works, however, remains to be seen. During an interview in early October, Ax hadn’t yet received all of the new music.

“They’ve all agreed,” said Ax, who then laughed at the futility of expecting composers to follow precise instructions. “I certainly hope so. But you never know. You can’t really dictate to people what to write. I talked to all of them, and they all said, ‘Yes, that sounds like a nice connection.’ And they’re going to try and stick it in. So let’s hope for the best.”

Ax doesn’t expect the composers to look for more specific inspiration. He didn’t ask Muhly, for example, to somehow connect his songs to Brahms’ Four Serious Songs, which von Otter will sing on the same program. “We just said Brahms,” he said. “We have what we hope will be pieces from various composers that are somehow, maybe, channeling Brahms.”

Ax chose the four composers with the help of artistic staffers at the CSO, Carnegie Hall, the L.A. Philharmonic and Cal Performances. “Anders Hillborg — I head some stuff of his in L.A., which I liked a lot. And I was playing on a couple of programs where his pieces were done, so we got to know each other a bit. We thought that would be a nice choice.

“We chose Nico Muhly mainly because of Anne Sofie. She wanted something from him. Brett Dean is a guy who I think is fantastic. He wrote a violin concerto for Frank Peter Zimmermann, which I love. [The concerto won the prestigious Grawemeyer Award for Music in 2009.] And we chose Missy because two of the staffers recommended her very highly. She’s studied with David Lang in New York. I met her, and she’s a very interesting lady. I’m looking forward to this a lot.”

One of classical music’s rising stars, Muhly is familiar to CSO audiences. The CSO has presented two world premieres by the composer. MusicNOW audiences heard his Step Team, a work for nine chamber players, in November 2007. James Conlon led the CSO and the 5 Browns piano ensemble in Muhly’s The Edge of the World at Ravinia in 2011. Now in his early 30s, Muhly has worked closely with Philip Glass. This season, the Metropolitan Opera presents Muhly’s 2011 opera, Two Boys, which is based loosely on the true story of British teenagers caught up in an online web of deceit and murder.

Music by Dean has turned up on CSO chamber concerts and on the MusicNOW series. In April 2013, guest conductor Sakari Oramo led the CSO in the composer’s Amphitheatre. The orchestra performed Hillborg’s Exquisite Corpse in 2005. Mazzoli, however, is a newcomer to the CSO’s commissioning roster.

The story that Brahms modeled his F-A-F theme on Joachim’s personal motto has long been part of classical music lore. But a few scholars have questioned the whole idea. There’s no direct evidence from either Brahms or Joachim, they argue, that supports the claim. The tale, told in highly flowery language, turns up only in an early Brahms biography by Max Kalbeck.

Ax isn’t particularly concerned that his Brahms Project, with its emphasis on F-A-F, might be based on an anecdote that isn’t true. “I don’t really care,’’ he said serenely. “I think it might be fiction. I’m happy to believe in it, especially since I think the Third Symphony starts with that. But the music is the thing; if it’s good music, then whether the story’s true or not doesn’t make any difference. F-A-F is just a way to overtly connect to something.”

A force on the international music scene for nearly 40 years, Ax is noted for his way with Mozart, Beethoven and Romantic-era composers such as Brahms, Schumann and Chopin. But contemporary music is important to him as well. He has given premieres of works by John Adams, Christopher Rouse and Krzysztof Penderecki.

“Contemporary music is important because music should be a living thing,” he said. “It’s fun. It’s exciting to have the possibility that you might be involved in learning something that’s going to last. It’s very thrilling. Imagine being the first person to conduct The Rite of Spring. It’s something special and a great honor. It’s exciting to discover something that’s not played all the time, something that’s new and wonderful.  I don’t see it as a duty. I see it more as a challenge and a pleasure.”

It’s a pleasure as well for Ax to perform with colleagues such as Ma and von Otter. “Anne Sofie and I have mutual friends, and she wrote me that she’d like to try something. So of course I leaped at the chance. She’s an incredible artist and what an opportunity for me to be on stage with her. And Yo-Yo, we have 40 years of partnership. I never think of doing anything that involves cello without Yo-Yo. I don’t think I’ve played with another cellist for decades. I can’t conceive of doing anything like this without Yo-Yo. I just wouldn’t have done it. I’d have to come up with a different program.”

For Ax, performing with such artists as von Otter and Ma, as well as CSO guest conductor Bernard Haitink, also is a kind of reward. Haitink led the CSO in concerts Oct. 31 and Nov. 1-3 featuring Ax as soloist in Mozart’s Piano Concerto No. 27.

“I always think that it’s a privilege to be on stage with people like that,” Ax said. “It’s a reward for practicing hard and being lucky enough to have a career in music. It’s a privilege.”

Wynne Delacoma, former classical music critic of the Chicago Sun-Times, is a freelance arts writer and lecturer.