Every musician has a special connection with their instrument, but while most play their own on stage, with pianists this is rarely the case. We practise at home, but we perform on instruments – cumbersome and costly to transport – that belong to concert halls, and which we won’t have touched prior to setting foot in the building.

The moment of first contact is significant. You enter the hall; the instrument is on the stage; you approach, take off your watch, empty your pockets of wallet and phone, sit down, adjust the bench … All the while somebody from the hall stands nearby, also expectant: for you, this is just one piano of many, but for them it is the only piano that matters, and they can care deeply about the way you react to it. You play something: a chord; a passage; a few bars. At once the piano ceases to be a generic specimen of the grand piano genus, and becomes the most concrete, tangible thing there is. This is the piano you are going to play tonight, and your encounter has just begun.

Piano lore can be summarised thus: there are good and bad pianos. This is the basic fact in a pianist’s life. Both kinds are to be found in all sizes, from all manufacturers, at any price point. A concert grand costing more than £100,000 can be bad. Smaller can be better than larger, but between two good pianos, the sound of the larger will be richer and more present.

One can get used to any piano, even when the instrument is terrible, but the better the piano, the less time is required, and vice versa. Spending time with a good piano is rewarding: there is always something more to discover in its tone. A bad piano functions in what-you-see-is-what-you-get mode, producing the same sound even after hours of practice. And each piano is unique. Manufacturing involves hundreds of processes and adjustments, most done by hand, all affecting the final tone. As a result two pianos of the same model, made in the same year, will sound different to the untrained ear, despite their outward sameness. The contrast in sound between different models, or between pianos made in different years or from different companies will be even more apparent.

Wouldn’t it be grand … Photograph: Alamy

This element of uncertainty adds to the stress of each concert. A good piano’s ability to influence playing can, however, like a good conversation partner, offer new interpretive directions; instead of forcing our will on the instrument, we are flexible, remain attentive to its tonal character and try to connect with it in an organic way. And so each concert becomes a voyage of discovery and you are kept alert, curious to find out how the Beethoven, the Ravel or the Rachmaninov will sound tonight.

From those first notes, you know right away. There is always room to get used to the instrument, but no amount of practice will change “don’t like” to “like”. A piano that feels the natural continuation of one’s hands can help a pianist forget his worries and become engrossed in the music. A bad piano can heighten feelings of insecurity, treacherously ruin concentration (always at the most dangerous moment), and make even the best-prepared players trip and fall.

It would be grand if we were able to turn “cooking pans” (as Russians wryly call unsalvageable instruments) into perfect pianos through sheer willpower, but changing a piano’s tonal character is meticulous work for a skilled technician, taking hours if not days. Usually what you find on stage is all there is, hence the reason why an initial “like” is so gladdening.

But what is this “like”? My dream piano has a singing, translucent sound, rich, varied, with a long decay; every note is rounded and bell-like. It has a broad dynamic range. Bass, middle and top registers are uniform in colour; there are no weak or unclear areas; nor are there any overly bright or open ones. Mechanically, the keyboard is “even” (keys equally weighted); a touch neither too heavy nor too light, allowing full control over the sound. All of this unites into a whole larger than the sum of its parts that invites you to explore new areas and layers in the works you’re performing.

You can infer the “don’t likes”: a metallic or unclear sound that’s flat and unvaried; a narrow dynamic range; an uneven keyboard, lack of character, and so on. Perhaps my demands seem exaggerated, but it is when working with the finest materials and tools that an artist, in whatever field – whether music, painting or cookery – will achieve their best results.

First impressions out of the way, practising begins, and with it, a slow process of acclimatisation: the aural and tactile equivalent of eyes adjusting to darkness. Our ears need to get used to the way the sound carries in a particular hall, our fingers need time to adjust to this specific keyboard. Hours pass, and the sound becomes fuller, deeper, you have more control over hues, the piano feels less like strange, uncharted territory.

Finally the concert. Hands are lifted to the keyboard and … wait, is this the same piano? Nearly always a small (or a big) surprise awaits in those first notes. The presence of the audience has changed the hall’s acoustics unrecognisably, and we need a little time – or half the concert – to readapt. Even the most intensive practice cannot compare with your concentration levels in a concert. The silence is different, too: that of an empty hall is much weaker than the live, breathing silence of attentively listening people. I often feel that, in these moments, nothing exists besides audience, piano, music and player, all united by the silence.

We finish the concert in full knowledge of the piano’s secrets: no corner remains unexplored. If it is a good instrument, then we are left with warm feelings for, and an intimate acquaintance with, what was a complete stranger only hours before. And, invariably, leaving the following morning, heading to another town and another hall, in which there is another unknown piano, that affection is tinged with sadness after our brief encounter.

Boris Giltburg’s debut CD, Schumann: Piano Music, is available on the Naxos label.