Gaspar Cassadó: Improvisation on The Blue Danube by Johann Strauss II
Yuriy Leonovich, cello
Kristin Leonovich, piano

Gaspar Cassadó composed and arranged a remarkable amount of music for the cello, but many of his works remain almost entirely unknown outside the instrument’s historical repertoire. Some pieces are hidden in archives. Others survive in recordings but have not entered regular performance. Still others are known primarily through a recording that preserves only one of several possible forms of the work.

His Improvisation on The Blue Danube, based on Johann Strauss II’s famous waltz, belongs to that last category.

Cassadó recorded the piece with the pianist Otto Schulhof. For a rare work by a great cellist-composer, a recording by Cassadó himself naturally carries considerable authority. It allows us to hear his timing, elegance, flexibility, and sense of style in his own music.

But the version my wife Kristin and I performed in the recording above differs significantly from the one Cassadó and Schulhof recorded. It is longer, includes some different piano writing, and, most noticeably, comes to an entirely different conclusion.

In Cassadó and Schulhof’s recording, the work seems to recede at the end, closing with an alternate ending that trails off on a dominant chord. In the source used for our performance, the return of the opening material leads instead into a brief but brilliant virtuoso coda. The difference is only eleven measures, but it changes the character of the whole piece.

A Blue Danube in D-flat major

Cassadó was not the only composer to hear Strauss’s Blue Danube as material for a substantial concert work. In 1898, Max Reger composed an Improvisation über den Walzer “An der schönen blauen Donau” for solo piano. The connection is especially striking because Reger’s improvisation and Cassadó’s paraphrase are both in D-flat major.

In Cassadó’s case, that choice is anything but obvious. Strauss’s principal waltz is in D major, a beautifully resonant and comfortable key on the cello. Cassadó moves the selected Strauss material down by a semitone, placing the work in D-flat major instead. This is not a transposition that simplifies the cello writing. On the contrary, it often makes the instrument work harder, replacing the natural resonance and open-string possibilities of D major with a darker and less immediately convenient tonal world.

Whether Cassadó knew Reger’s improvisation or whether the shared key is simply a remarkable coincidence, the parallel is fascinating. Two very different virtuoso musicians took the same celebrated Strauss waltz and recast it in the same unexpected key.

The musical results, however, are very different. Reger’s work transforms Strauss into something unmistakably Reger-like: dense, chromatic, expansive, and pianistically elaborate. Cassadó’s piece retains far more of the grace, sweep, and sparkle associated with the waltz itself. Yet the move to D-flat subtly alters its color. On the cello, the familiar music acquires a warmer, more veiled, and slightly more luxurious sound, even as the transposition increases its technical difficulty.

In that sense, Cassadó’s musical language also looks backward. Heard beside the Strauss paraphrases of Eduard Schütt or the Strauss metamorphoses of Leopold Godowsky, the piece feels less like a modern response to Strauss than a continuation of an older concert-paraphrase tradition. By the early 1950s, that language already belonged to an earlier world: lush chromatic turns, grand transitions, ornamental figuration, and virtuoso theatricality point far more naturally to the late nineteenth and early twentieth centuries than to Cassadó’s own decade. But that is part of the piece’s charm. Cassadó was not trying to modernize Strauss. He was entering the vanished world of the Strauss paraphrase and making it speak through the cello.

More Than a Familiar Waltz for Cello

At first glance, a cello paraphrase on The Blue Danube might seem like a natural encore: a famous melody transformed into something elegant, charming, and recital-friendly. Cassadó’s piece has all of that surface appeal, and it is beautifully suited to the cello. But it is considerably more ambitious than a straightforward arrangement of Strauss’s best-known waltz.

The work does not simply present Strauss’s material in its original sequence with cello figurations added on top. Cassadó begins with an atmospheric introduction based on material from the fourth waltz, creating an expectant opening before the familiar first waltz appears. From there, he selects, reorders, and combines passages from Strauss’s original, moving among different waltz ideas with a freedom that makes the piece feel newly shaped rather than merely transferred from orchestra to cello and piano.

The middle of the work is especially revealing. Instead of simply continuing from one recognizable tune to the next, Cassadó expands the material into a developmental passage of his own. Familiar gestures are reshaped, extended, and placed into a new dramatic progression. The piece still belongs unmistakably to the world of Strauss, but it is no longer simply The Blue Danube reduced or decorated for cello. It has become a real concert work with its own pacing, architecture, and sense of arrival.

That is one of Cassadó’s great strengths as an arranger. He understood that a successful transcription is not always a matter of reproducing the original as faithfully as possible. Sometimes it means discovering what the music can become on another instrument. His cello writing does not merely sing Strauss’s melodies. It dances, ornaments, accompanies, launches into passagework, and takes on the physical theatricality of a virtuoso cello piece.

The Return of the Opening

Near the end of the version heard here, the music returns to the atmosphere of the opening. The gesture is immediately effective: after the motion and variety of the waltz episodes, the introductory material comes back as a point of recognition and return.

That could have been an entirely satisfying conclusion. The music has come full circle, and the return of the opening material gives the work a clear formal shape.

But in this version, Cassadó does not stop there.

After the return, the piece breaks into a final virtuosic coda. It is compact, sparkling, and unmistakably theatrical. Suddenly, the work is no longer simply looking back at the elegance of Strauss’s ballroom. It is standing at the front of a concert stage, asking the cello and piano to finish with brilliance and command.

That ending matters because it confirms what the rest of the piece has already suggested: this is not merely a graceful arrangement of a familiar waltz. It is a fully conceived concert paraphrase, written for performers who can carry charm, lyricism, wit, and virtuosity in one continuous arc.

The Ending Cassadó and Schulhof Recorded

Cassadó’s recording with Otto Schulhof presents another version of the piece. It is shorter than the source used for our performance, with apparent cuts and differences in the piano writing. Most strikingly, it does not use the same concert ending. Rather than proceeding from the return of the introduction into the brilliant final coda, their recorded performance concludes with an alternate ending on a dominant harmony, leaving the sound unresolved.

There is something attractive about that ending, too. It leaves the piece suspended, almost as though the waltz has drifted out of view rather than arriving at a formal curtain call. It may have suited the recording, Cassadó’s conception at that moment, or a later performing revision of the piece. Without further source evidence, it would be unwise to claim exactly why the two versions differ.

But the musical effect is unmistakable.

The recorded ending makes the work feel lighter, more fleeting, perhaps more improvisatory. The ending preserved in the source used for our performance makes it feel more substantial and public: not a waltz memory disappearing into the distance, but a concert piece reaching its final flourish.

Neither ending erases the other. Instead, the difference reveals something valuable about Cassadó as a performer-composer. His own recorded performance does not exhaust the possibilities of the piece. The surviving source preserves another conclusion, one that shows just how fully he could turn Strauss’s familiar waltz into a brilliant recital work for cello and piano.

A Rare Piece Worth Hearing Again

Cassadó’s major transcriptions and original works deserve far more attention than they receive. His arrangements of Albéniz, Chopin, Debussy, Granados, Paderewski, and others reveal an extraordinarily imaginative musical personality: a cellist who did not merely borrow music from elsewhere, but understood how to make it live naturally through the cello.

His Improvisation on The Blue Danube offers a particularly appealing glimpse of that art. Strauss’s melodies are familiar, but Cassadó’s handling of them is anything but routine. The piece belongs to a tradition that includes Reger’s piano improvisation on the same waltz, as well as the late-Romantic Strauss paraphrase world of Schütt and Godowsky. Yet Cassadó’s solution is entirely his own: elegant, agile, theatrical, and inseparable from the possibilities and challenges of the cello.

The performance above adds another layer to that story. Cassadó and Schulhof’s recording allows us to hear the piece in the composer’s own hands, but it does not preserve the brilliant concert ending found in the source used for our performance. Hearing that ending changes the work. It gives the final return a different purpose, transforms the last moments into a true virtuoso arrival, and makes clear just how confidently Cassadó imagined the piece as a recital showpiece.

For a work that has remained so little known, that difference is not a footnote. It is part of the reason the piece deserves to be heard again.