Written by Oscar Holland, CNN

CNN Style is the international digital news partner for the RIBA International Prize. Over the coming weeks we will be profiling the four finalists for the 2018 award.

Tasked with designing a music school in Tokyo, architect Tomohiko Yamanashi sat down with tutors and students to determine what they wanted from their new campus. He found that their priorities -- sunlight, natural ventilation and visually open practice spaces -- were completely at odds with how most music institutes are designed.

"Usually, architects put a central corridor in the building, dividing both sides into same-sized lesson rooms," he said in a phone interview. "As a result, the atmosphere of the building is very similar to that of a prison."

So Yamanashi, who works at the Japanese architecture firm Nikken Sekkei, decided to entirely defy expectations of what a music school should look like.

The Toho Gakuen School of Music, in suburban Tokyo. Credit: Nikken Sekkei

His design's boxy concrete exterior is softened by glass-walled practice spaces and generous use of wood. Instead of linearly-arranged, isolated rooms, the architect opted for what he called a "porous" layout -- one that that encourages sound, light and people to flow freely throughout.

This unconventional approach appears to be vindicated: The Toho Gakuen School of Music was last month named among four finalists in the RIBA International Prize, a biennial award honoring the world's best new buildings.

Creating atmosphere

The orthodoxy of music school architecture emerged, in part, from rational design concerns: A desire to sound-proof practice rooms often results in thick walls and the sacrifice of natural light.

But Yamanashi believes that having sound escape is not only bearable -- it's desirable.

"Architects worry too much about acoustics," he said. "If you walk around the corridors and there is no sound leaking from the lesson rooms -- I hate that kind of image. Sound leaking from room to room is a very big problem, but sound leaking out to the corridor is actually very important for creating atmosphere."

The glass-walled practice rooms increase natural light and encourage eye-contact between musicians. Credit: Nikken Sekkei

Acoustic engineering nonetheless played its part. The 62,000-square-foot school is fitted with ceiling panels and timber cladding that prevents "flutter" echoes (which occur when noise bounces between two reflective surfaces).

Yamanashi also adjusted the size and proportions of each practice room to match the needs of specific instruments, from large rooms for drums to the intimate settings preferred by the school's violin tutors.

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The use of glass walls, rather than concrete ones, allows the sound of music to float through the school's public spaces. But the layout ensures that practice spaces never touch, ensuring they remain insulated from one another.

Another consequence of clear walls is that students can -- unusually, for a music school -- see one another practicing. This too has its benefits for students, Yamanashi said.

Natural light enters the basement floor via sunken gardens. Credit: Nikken Sekkei

"When you play in an orchestra, the most important thing is eye contact between the musicians. But usually, if you're in a prison-like space, there's no eye contact between the players. I wanted to make some kind of transparency.

"Students have to spend such a long time in the lesson rooms," he added. "If we can give them some kind of vista or spacious atmosphere, it helps them relax.

Textural considerations

The school's unconventional layout is reflected in its bold, pixelated exterior. Just like its floor plan, the building's concrete facade comprises a collection of interlocking squares and rectangles of varying size.

The architects opted for textured concrete, rather than a smooth surfaces, to give the exterior a more organic appearance. Credit: Nikken Sekkei

In turn, the exterior then reflects and interacts with the texture of the neighborhood. Chofu, a Tokyo suburb located about 12 miles from the city center, is a largely residential area made up of small houses, so Yamanashi broke up the school's outer surfaces to help assimilate them with their surroundings.

"We aimed to create a sense of scale and an appearance that matched the surrounding detached houses," he said. "We wanted (it to look like) random and natural scenery at a glance, like an old village."

Rather than relying on monolithic planes of smooth concrete, Yamanashi gave the school's outer faces a rough, fragmented texture to integrate them with the local architecture.

Glass and wood soften the appearance of the building's concrete frame. Credit: Nikken Sekkei

"With that kind of effect, concrete starts to look more softened -- like soil," he explained. "For me, that's very important, because around (Chofu there) are many many Japanese-style houses made from wood and soil."

Yet, for all the considerations made by Yamanashi and his team, the recently opened building once stood on the brink of obsolescence. According to the architect, a change in school management during construction threatened to halt the project. Even after the new regime agreed to persist with his unorthodox design, it was only on the grounds that it would serve as a temporary home before being converted into storage space.

But now, Yamanashi said, the building's future is secure. Plaudits from the architecture world will only have helped his case.

"I visited the head of the school, and he told me that they had decided to use our design as a graduate school, so it will survive -- it's a result," he said. "Students and staff like our facility very much."