In the decades following World War II, Japan had a lot to rebuild and a coterie of maverick modernists up for the challenge. Over time, many of those vintage buildings have come under threat or, worse yet, come down entirely. But Maru Architecture’s conversion of the former Ueno City Hall into a municipal library and hotel makes a strong argument for repurposing instead of replacing midcentury works.

Located in Mie Prefecture’s Iga City (as Ueno is now known), the project began with public outcry—a rarity in Japan. Most of the time, protests are minimal or go unheeded, as in the case of Kenzo Tange’s Kagawa Prefectural Gymnasium. Despite vigorous opposition by an international group of concerned citizens and design professionals, the gym’s demolition started in April, ostensibly on the grounds of functional obsolescence and structural weakness. In Iga, with a new city hall in place on a separate site, the plan was to take down the tired old one designed by Junzo Sakakura in 1964. Instead, the local government listened to constituents who advocated saving Sakakura’s building, and in 2019 granted it Important Cultural Property status, guaranteeing preservation.

The officials envisioned turning the historic structure into the city’s main public library. In 2022, when a public-private-partnership was created to spearhead the building’s renovation, one of the participating entities, Maru, proposed pairing the library with a luxury hotel. Taking advantage of the tourism boom and helping offset high construction costs, the Tokyo firm’s scheme got the green light.

“On my first visit, I was struck by the building’s strong and beautiful composition,” recalls Maru principal Yohei Takano. Occupying a prominent site on the sloping approach to picturesque Ueno Castle, famous for its pristine white walls and tiered roofs, the original city hall was the centerpiece of a series of projects in Iga designed by Sakakura. Taking its cues from the gradually rising ground, he created a two­story horizontal structure defined by exposed concrete, piloti, and an open plan. No doubt these features bear the imprint of Le Corbusier, as Sakakura was one of three Japanese architects to train in his Paris atelier.

“I felt a great responsibility to the work of a great master,” comments Maru principal Sachiko Morita. Leaving the exterior largely intact, the interior was renovated in two phases, with the top­floor 19-room hotel opening last year, followed in April by the 400,000­ volume library concentrated on the ground and basement levels. “Guests can just go downstairs and grab a book,” jokes Takano. Bringing the building up to code required careful analysis and repair of the concrete and steel reinforcing, as well as adding shear walls for seismic resilience, placed discreetly so as not to obstruct the space.

While the hotel is accessed on the building’s castle-facing north side, the library is approached on the east side, where gentle steps lead up to its canopied doorway. Inside, the entrance hall is flanked by open book stacks on either side, with meeting areas and support spaces opposite. Once occupied by a sea of citizen­service desks, the south­side stack area is a vast space where the ceiling soars to 17 feet. Following the topography, a gracious stairway connects to another stack area on a mezzanine level to the north (with the hotel entrance, café, and shop beyond).

Additional stairs descend to the lower-level offices, storage, and children’s reading room and ascend to the former city council chambers on the second floor. Now a conference room, it sits between two courtyard gardens, with the hotel rooms ringing the floor’s perimeter. Existing skylights set within the slabs of the courtyards enable soft daylight to filter down to the heart of the library.

But there is no shortage of daylight at ground level either, where the original full­ height window walls wrap the library exterior. Set back from the facade above, the horizontal grid of steel sash and thin glass panes creates a sheltered outdoor space resembling an engawa, the covered porch often found on traditional Japanese buildings. Like shoji screens, the uninsulated glass barely separates inside and out. “On warm days, it’s warm; on cold days, it’s cold,” comments Takano. Nonetheless, the architects concentrated the library’s seating areas near the windows and located the swirl of bookshelves in the middle of the space. A new HVAC system, including radiant heat­ ing and cooling, keeps this area comfortable. Ideal for meandering, the curving forms of the shelves—collaborations with furniture designer Kazuko Fujie—were inspired by local wind currents and their steel frames by Sakakura’s elegant window sashes.

Preserving the windows—one of the city hall’s finest features—was required by the Important Cultural Property designation. In addition to saving the building, this official protection ought to elevate their value. In Japan, traditional wooden temples and Queen Anne–style train stations are revered, but concrete modernism is an important part of the country’s architectural heritage too.