Ever since it became fashionable to play without music, a number of well-proven memory techniques have evolved that have served musicians pretty well. Soloist and chamber music pianist Susan Tomes sums them up as intellectual, aural, muscular and photographic.

‘When I was learning and pieces were shorter, I could picture the music in my mind,’ she says. ‘As I got older and began playing more complex music by Schubert, for example, I found intellectual memory techniques – understanding the music’s shape and structure, location of bridge passages and so on – helpful, especially when photographic and muscle memory, an instinctive memory that is acquired over hours of practice, failed me.’

How to use a ‘visual memory’ to memorise music

Pianist Alexandra Dariescu, in turn, relies on what she calls ‘visual memory’. ‘It’s what I use the most,’ she says. ‘I can “see” where I am on the page but it only comes with huge amounts of concentration and after hours of “mental practice” away from the score. I can’t overstate how useful mental practice is. When I go for a walk or watch TV, my mind drifts and if I can shut out any noise and concentrate on that particular passage, I know I’ve got it.’

What is intellectual memory and how can you use that to memorise music?

Like Tomes, Dariescu also employs intellectual memory to lock down the notes. She’ll look for clues to the music’s shape and how it unfolds. She’ll reduce a passage to its harmonic essence, playing it as a sequence of chords. ‘The pianist Dinu Lipatti always analysed the score for a long time before even starting to sight read it, and I have adopted his technique,’ she says. ‘Of course, some musicians are born with a gift for memorising. I once asked pianist András Schiff about his skill at memorising. His answer was simple: “It’s a blessing”. But his kind of extraordinary memory can be achieved through lots of hard work and super-strong will power.’

Pianist Stephen Hough doesn’t claim to be ‘blessed’ with a great memory although accepts that by the time he knows a piece inside out, ‘I have memorised it’. He admits, though, that when faced with particularly challenging sections, he’ll fall back on intellectual techniques: ‘I will map out patterns, black and white notes, repetitive shapes and so on.’

What about memorising songs?

Much of this applies to other instrumentalists, with breathing and bowing providing additional aide-mémoires. Singers, though, face a different set of challenges, as soprano Lynne Dawson explains: ‘The verse nature of recital song can make it hard to memorise. You just have to find what works for you: mnemonics or straightforward repetition until it’s ingrained. Abstract subjects can be hard to memorise. Association helps – singing one verse in the hall, another on the stairs, and so on. Or creating a picture for each verse. It needn’t be literal; just something to prompt recall. In an opera, it helps that you are told where to stand and can associate a position with a word or phrase.’

How multi-layering can improve your memory

For Daniella Sicari, a multi-prize-winning soprano and postgraduate student at the Royal Northern College of Music who is busily launching her career, the challenges of memorising new repertoire are all too real. She relies on an approach she calls ‘multi-layering’. ‘Memorising a work begins with the text,’ she says. ‘That’s harder when it’s a foreign language so if it’s not one I’m familiar with, I’ll first do a poetic translation of it, which will help colour my interpretation, before a word-for-word, literal one. Next, I go to the piano to learn the music before combining it with the libretto. I’ll exaggerate the music’s colours and sense to embed it in my mind, at the same time conducting myself. I create an inner monologue, too, that helps me navigate the music and the text. If it’s opera, I take the same approach to a lesser degree with the other characters I appear with, so I understand how to react when not singing and to be aware of my cues.’ Her approach applies equally well to a recital such as lieder, she says, the role of other characters being taken by the accompaniment.

Hard work, in short, is the key. But, as my experience proves, when push comes to shove, you can’t entirely trust your memory. The great composers certainly thought so. Until the late 19th century, playing from memory was frowned upon, composers believing it trivialised their work, led to bad practice and turned performing into a circus act. Susan Tomes recalls the story of Beethoven chastising his pupil Carl Czerny for playing from memory, saying it would make him casual about his markings on the score.

Ironically, one of the first artists to overturn centuries of performance practice by performing from memory at the piano was Liszt, who was often shown gazing skywards, as if seeking divine inspiration. In truth, he performed only a fraction of his repertoire from memory and all of his own pieces from music, in case audiences thought he was making it all up as he went along.

Stephen Hough performs his own compositions from the music, too. ‘It’s partly because it helps me to separate “me” the composer from “me” the performer,’ he explains. ‘I don’t want any sense (in my mind or the audience’s) that I’m improvising.’

In fact, Hough’s adherence to the score isn’t confined to his own music: ‘If, or when, I begin to play Bach in public, I would definitely use the score.’ As for other composers, he says, ‘there is an argument (not entirely watertight but important) that a concert is theatre and, however well an actor might read a role or a poem from a book or even an autocue, it’s not quite the same as doing it from memory.’

Should musicians learn pieces by heart or is it acceptable to play from the score?

Hough admits it’s getting harder to memorise as he grows older (he’s only 57), which may lie behind his willingness to consider playing from the score. He wouldn’t be the first to wave the white flag. As they grew older and lost confidence in their memory, Clifford Curzon and Sviatoslav Richter performed fewer concerts from memory. John Gilhooly, director of Wigmore Hall, accepts older artists may feel more comfortable performing this way: ‘An older performer, perhaps a cellist playing the Bach cello suites, might ask if they can use the music, and that’s fine. And an older pianist performs here with his wife turning the music, but I’ve never seen him refer to it; it’s there as a crutch.’

Otherwise, Gilhooly is less tolerant of younger artists choosing to use the score: ‘The music stand can be a barrier between the audience and the performer, and the performer and the music. I get cross when I see a singer buried in the score. I don’t think performing from the music should become the norm and I don’t see any signs that is happening. People are paying a lot of money to hear an artist and they have certain expectations. But I also accept that an artist may be experiencing pressures that are making them feel vulnerable. You have to be understanding.’

Alexandra Dariescu agrees that audiences expect artists to perform from memory but is unsure where exactly that expectation comes from: ‘I think everyone should perform in whatever way they feel most comfortable and concentrate on what they want to communicate. Sometimes I wish I didn’t have to memorise pieces so I could spend more time learning repertoire, but it’s about prioritising, and attitudes differ between performers.’

They certainly do. Pianist Kathryn Stott can memorise easily and securely but says she prefers to play from the music: ‘You have to know the music sufficiently well not to be glued to the score. When it doesn’t work is when it’s being used because the performer isn’t prepared.’ In any case, she reckons the public doesn’t care whether music is used or not. ‘I played Rachmaninov’s Piano Concerto No. 2 the other night to 2,000 people and no one gave a monkey’s that I played it from the music. Times are changing and more performers are doing it because they know people come to hear the music, not see what your memory’s like.’

Although Susan Tomes performs recitals from memory she can understand why some of her fellow performers do not. ‘So many students and colleagues have told me about the worry and distress that memorising – and public lapses of memory – have caused them that I have come to feel that, although it is liberating for some, it is burdensome for others and probably causes more unhappiness than it’s worth.’

In any case, like Kathryn Stott, she fears the audience may not even notice when a performer plays from memory. ‘I gave a recital last year and my friend who came along was surprised when I told her I played it from memory. She hadn’t noticed – so why do we do it?’