Joan Blackman has a bone to pick with Peter Ilich Tchaikovsky. According to Vetta Chamber Music’s artistic director, she’s had to play fast and loose with the late, great Russian’s instructions for his Souvenir de Florence, for one simple reason: he “didn’t know what he was talking about”.

She’s referring to a moment in this rarely performed string sextet where the first cello has a moment in the spotlight, yet the other five musicians are asked to play fortissimo, or very loudly. And this, she says, just isn’t going to happen.

“We have to sound more like a pianissimo orchestra accompanying,” Blackman explains, on the line from her Vancouver apartment. “Even though it has to look exciting, and it has to sound exciting, it just doesn’t work otherwise.…And Tchaikovsky knew it was going to be a problem; he confessed to his brother that he didn’t know what he was going to do with the six voices. But then he was boasting afterwards: ‘Oh, what a great fugue!’ apparently.”

Less musically astute listeners might have another quibble with the piece: although it was named for the Tuscan capital, its only Italianate moments surface in the second movement, when the pizzicato strings briefly conjure up a plucked mandolin or guitar. Otherwise, as Blackman notes, it’s as Russian as Russian can be. But there is some intriguing Italian content in Vetta’s upcoming Seriously Strings concert, in the form of another under-performed work, Giacomo Puccini’s Crisantemi, a brief requiem for his friend and patron, the Duke of Savoy.

“It’s simple, but not very simple,” Blackman says of this rare venture into chamber music from the great opera composer. “Somebody in our group said they’d never played it before, and someone else said, ‘Oh, it’s simple.’ And I thought, ‘Yeah, but it’s not simple to make it sound beautiful.’ ”

Crisantemi is a quartet; Souvenir de Florence is, as noted, a sextet. In between, naturally enough, the Vetta players will essay a quintet, Wolfgang Amadeus Mozart’s Viola Quintet in G Minor. (For this week’s three performances, Blackman will be joined by her fellow violinist David Gillham, violists Nicolò Eugelmi and Tawnya Popoff, and cellists Joseph Elworthy and Rebecca Wenham.)

For Blackman, this late-career composition represents peak Mozart: it is darker than many of the Viennese composer’s commissioned works, yet retains the former child prodigy’s penchant for humour and surprise.

“He just goes from tragic to more tragic, and then all of a sudden, at the end, there’s this cute thing, like ‘Oh, nothing ever happened. Hahaha,’ ” she says, laughing. “He was exploring all of this very personal, tragic stuff with the G-minor key—and then, all of a sudden, ‘Forget it: G major!’ So maybe he’s laughing at himself, or just saying ‘Okay, there’s all that, but let’s just forget it.’ Who knows? They didn’t have psychologists back then.”

More than three centuries on, Mozart’s motives remain obscure, but Blackman is well aware why she’s making this particular work Seriously Strings’ centrepiece.

“I will never get tired of playing it,” she says, “and I believe people love to hear it, too.”

Vetta Chamber Music presents Seriously Strings at West Point Grey United Church at 2 p.m. on Thursday and 7:30 pm on Friday (November 23 and 24), and at Pyatt Hall at 2 p.m. on Sunday (November 26).