What, precisely, did Beethoven tell his future performers? The Boston Globe’s Jeremy Eichler sat down with Borromeo Quartet’s first violinist Nicholas Kitchen in advance of the kickoff to the BSQ’s first concert in its Beethoven cycle in Boston to chat about the discoveries he made in the German master’s manscripts.

Violinist Nicholas Kitchen’s discoveries in Beethoven may be “one of those remarkable breakthroughs in music that come only once every few decades”

Lost Between the Lines: Nicholas Kitchen’s quest to decipher long-hidden markings in Beethoven’s Original Quartet Manuscripts.

"Listen to Bach Transformed for String Quartet...On its most recent album, the Borromeo String Quartet goes back to the source with a transcription of the first book of Bach’s “The Well-Tempered Clavier,” originally for keyboard solo, by one of the ensemble’s violinists, Nicholas Kitchen."

"Opening the evening was Mozart’s String Quartet No.18 K465, deftly done with delightful assurance and lithe textures. But the night’s apex came with Platt’s gritty ode – to Beethoven, to Frost, and to the superb Borromeo players."

"The Borromeo Quartet plays with great finesse. Intonation in its ensemble was as close to perfect as you can get. The dynamic range went from a whisper to full-out playing. But the best aspect of the performance was the sensitivity to the differences in style among the composers."

"This is a quartet with an unusual dynamic range and an unfailing commitment to a unified, ensemble sound and approach ... softness with a surprising amount of intensity ... and in the loudest passages, you had the feeling [the Borromeo] were never forcing anything, but just allowing the music to emerge of its own accord."

"It was nothing less than astonishing to note how different Borromeo made Op. 130 sound: instead of that driving force most ensembles bring to Beethoven, Borromeo released each movement’s buoyant internal propulsion. These players uncorked Beethoven’s champagne, and it proved a most worthy celebration."

"I don’t think my ears are accustomed to the detailed musicianship that the Borromeos brought to the table. This performance could well fall under the discipline of eschatology — the metaphorical "end of ordinary reality and reunion with the Divine.”

"They’ve been presenting complete Bartók cycles for more than a decade, and their ingrained knowledge of these works could be heard in their polished performances. In such experienced hands, vivid colors and rich detail animated every movement. Interestingly, the quartet played from full scores, reading from laptops mounted on their music stands."

"The beauty of classical music is a great composer makes music that’s both instinctive and simple, and ingenious and complicated, all at the same time,” Kitchen said. “When we study the works, we want to learn all the details, and that involves reading the complete score."

"No other concerts I’ve heard this summer can come close to the thrill I experienced hearing the Borromeo Quartet."

"Most artists can go to extremes when needed; then there are those who seem to positively thrive there — Caravaggio, Almodóvar, Nirvana. The Borromeo Quartet, too."

"The Borromeo Quartet walked into Jordan Hall Wednesday night and gave what was easily the most profound and intellectually engaging experience I have had this concert season."

"Though not the first Bartok marathon in my experience, it was the most intense, performed at a high standard that brought you so deeply into the music's inner workings that you wondered if your brain could take it all in ... The music's mystery, violence, and sorrow become absolutely inescapable."

"The quintessential American quartet, the Borromeo, transforms its concerts into events both audible and visual."

"There really is something different about the Borromeo’s ensemble. They are always cohesive and focused as a group, but there is a remarkable freedom in their musical interaction... This was in fact the first time I have heard a really successful traversal of the three last quartets, either in the concert hall or on a recording."

"The digital tide washing over society is lapping at the shores of classical music. The Borromeo players have embraced it in their daily musical lives like no other major chamber music group."

"The Borromeos use recordings to reveal their progress and deep musical knowledge to audiences."

"The four movements of Schubert's quartet had everything a listener could want: drama, intensity, passion, delicacy, exceptional lyricism and interesting lines. The Borromeo played with a controlled abandon that was not only immaculate but left the audience wanting more."