Watch this. A couple in their mid-80s, married for 65 years, play the piano. Their hands – the skin of which is smooth, shiny and unwrinkled, as if washed clean rather than marked by the decades – don't so much play the keyboard as conjure sounds from it. Their playing dissolves the difference between them and the instrument, and between each other. Their arms criss-cross, as if their four hands make a single composite player; their gestures, their open-mouthed wonder at and commitment to the music (a sequence of pieces by the husband, and transcriptions of Bach), and their smiles to each other, are touchingly similar. They even look alike, with their glasses and short grey hair, their posture at the piano. What you're seeing is private, intimate music-making raised to the level of a joyous miracle. It's one of the treasures of 20th- and 21st-century music.

Hungarian composer, pianist, and teacher György Kurtág and his wife Marta have been playing Kurtág's Jatekok (Games) for the past 40 years, and that ever-expanding set of pieces is just one of the laboratories in which Kurtág has conducted his experiments in the search for musical truth. It's a compositional journey that has often involved reducing music to the level of the fragment, the moment, with individual pieces or movements lasting mere seconds, or a minute, perhaps two. In fact, Kurtág builds whole cycles of pieces from these small shards, like his blistering Kafka-Fragments for violin and soprano, a 40-movement song-cycle of unflinching emotional and existential rawness, or the 12 Microludes for String Quartet, each a shred of pure musical extremity: violence or stasis, complexity or simplicity. Kurtág's apparent obsession with this smallness of time-scale isn't some kind of post-Webernian quest to split the musical atom or to find the structural essence of music. Far from a "reduction", Kurtág's fragments are about musical and, above all, expressive intensification: maximising the effect and impact of every note, every gesture. Listen to any of the Kafka-Fragments to hear what I mean.

Despite their brevity, these tiny pieces are not incomplete as experiences. Take, for example, the seven notes of Flowers We Are, Mere Flowers … ( … embracing sounds) – whose title takes almost as long to read as the piece does to hear – part of the 8th book of Jatekok. (You hear it from 4'10'' into the Kurtágs' performance.) Kurtág precedes the piece with a prelude of nine tolling B flats; the seven notes of Flowers We Are … follow. What you hear are the notes of the C major scale turned into a meditation for four hands. There is nothing more familiar than these elements, but nothing stranger than what happens to them throughout this performance. Paradoxically, precisely because of its conciseness, the piece becomes static and timeless; and those notes, far from meaning anything like "C major" or "tonality" are unmoored from conventional function and allowed to resound and shimmer in a much larger musical space. Hearing Flowers We Are … is like opening a trapdoor in your floor and dropping for a moment into the infinity of the cosmos.

That kind of intensity is something that Kurtág is always looking to create. Often, that's about an expressive or expressionistic violence (hear The Saying of Peter Bornemisza for soprano and piano, or the Messages of the Late Miss RV Troussova for soprano and ensemble to experience some of Kurtág's most emotionally shattering music), but it's just as often about wresting images of beauty and solace from a world of darkness. Some of Kurtág's most beautiful pieces are the ones he has composed as memorials for friends or musicians. They are often pieces that use that paradoxical power of the fragment to suggest a timelessness or spaciousness, for example In Memoriam Andras Mihaly, another of the Jatekok.

The detail of Kurtág's compositional imagination is matched by the inspirational and sometimes forbidding fastidiousness of his teaching of the whole repertoire of classical chamber music and his coaching of his own music. His near-perennial state of dissatisfaction with performers is the stuff of legend among musicians, but so too is the brilliance of his insight and wisdom. And any frustration with his interpreters is matched by a much deeper and more lacerating strain of self-criticism: "I never hear my ideas properly ... No one can hear it … There's nothing to be done … I felt I couldn't go on, I mustn't go on …" – just some of the Beckettian aphorisms that stud his interviews with Balint Andras Varga. (A mirror image can be found in his unconditional admiration for the music of his friend György Ligeti, whom he first met in 1945: "I … love this music from the bottom of my heart, which resounds in Atmosphères as if it welled up inside me, which shakes me so in the Dies Irae [of Ligeti's Requiem], which lifts me on high in the violin concerto.")

Kurtág's music for orchestra has embraced a larger scale in pieces such as Stele, composed for the Berlin Philharmonic and Claudio Abbado, and … concertante … for violin, viola, and orchestra. The three-movement Stele is memorial music that is nonetheless filled with a strange luminescence: the reverberating chordal repetitions in the final movement sound like the tolling of funeral bells (or perhaps the breathing of alien life forms). The first movement is an adagio, an implacable lament that ends with a homage to Bruckner in a passage for four Wagner tubas. But the second movement has the most scintillating moment of all. In the middle of the music's desperate violence, there is a sudden image of strange stillness, a sound made by six flutes, a tuba, and a piano. Kurtág said he wanted the effect to be like "the scene in Tolstoy's War and Peace where Prince Andrei is wounded at Austerlitz for the first time: all of a sudden, he no longer hears the battle but discovers the blue sky above him. That is what the music conjures up." He continues, lamenting that, "I keep telling this story and no one responds." But they do, György! If you are open to it, the devastating poetry of Stele can sear itself on your soul.

This can only give you a small slice of Kurtág's world. Ever since the piece he thinks of as his opus 1, a string quartet written in 1959 after a year of psychoanalytic soul-searching in Paris, Kurtág has composed a huge catalogue that resonates with the music of the past he loves most – Bach, Schubert, Schumann, Beethoven, Bartók, Webern. It also speaks with a fearless directness that bypasses musical tradition and becomes its own idiom. When you hear it in a performance such as the Kurtágs' own, his work creates a world of apparently unmediated feeling. It is full of the joys and despairs of life, which you can see, etched in the faces of György and Marta as they play.

Five key links

Jatekok in performance by the Kurtágs

Stele

12 Microludes



Messages of the Late Miss RV Troussova



… concertante …

