Underground Library by Hiroshi Nakamura & NAP


Hiroshi Nakamura and NAP Architects designed a new reading space in Kurkku Fields, Japan that burrows readers and bookworms into the green architecture enveloped with fields of grass. Surrounded by greenery, the underground library aims to be a reading nook for people who seek comfort and the joy of reading while within the reach of nature. In the fall of last year, Kurkku Fields also unveiled a cocoon villa where guests can experience a life they crate in the open and a new form of nature, living things, and human activity.


As the name suggests, Hiroshi Nakamura and NAP Architects turn the underground library in Japan into a safe space hidden under the ground, a refuge nestled in the earth like a cave rather than towering above the ground. The reading space is located in the middle of the land which has been characterized by a mortar shape. While wandering around Kurkku Fields, people suddenly find the library’s entrance, ushering them to dive into the earth and encounter an unexpected realm driven by architecture and books.

underground library japan kurkku fields
images courtesy of Kurkku Fields and Hiroshi Nakamura and NAP | photos by Kohei Omachi and Yuka Yanazume



Filled with around 3,000 books


At the time of its opening on February 16th, the underground library at Kurkku Fields by Hiroshi Nakamura and NAP Architects houses about 3,000 books with a selection of books centered on nature and agricultural life, with a unique expansion and connection to poetry, philosophy, history, religion, science, and economics. Passing through the bookshelves reveals a hall with natural light coming in from the ceiling.


Guests staying at Villa Cocoon and another neighboring accommodation can spend a night in the fantasy-like underground library in Japan bathed in soft light even after its closing time. Just as plants and vegetables grow with microbes in the soil as nutrients, people burrow into the ground to read books, accumulate knowledge, cultivate the power of imagination, and step on the earth again to move forward into the future.

underground library japan kurkku fields



beams and columns disappear


The underground library is infiltrated by wooden elements to thread the harmonious continuity of tranquility during reading hours. Architectural elements such as beams and columns disappear to make way for the circular sunroof that echoes the look of a mole’s hole. The internal ceiling height slopes as the elevation shifts, and a small hidden room is carved in one of the spaces to offer privacy to the reader. 


The floor, walls, and ceiling are planted with a soil finish, and the grass that is injected into the vertical surface of the slab edge hangs down, giving the space a sense of moisture. This is a detail that allows caretakers to adjust the balance between irrigation and water retention depending on the season. 


The design team, led by Hiroshi Nakamura with books selection by Yohei Kawakami, finds the underground library’s heart in the midst of the earth’s essence. They believe in the wonders of nature as the source of all life and the symbol of motherhood, all revered and respected. It is rightly so to retain such value laid upon the primary daily-life resource of people, and the design team infuses its idea of a peaceful place cultivated to let living beings and organisms grow along with the readers’ knowledge.

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project info:


name: Underground Library

architects: Hiroshi Nakamura and NAP Architects

location: Kurkku Fields in 2503 Yana, Kisarazu City, Chiba Prefecture, Japan