Recently, I had the opportunity to visit Akiyoshidai in Yamaguchi Prefecture. Akiyoshidai is known as one of the largest karst plateaus in Japan. Across its gently uplifted terrain, limestone is scattered, and beneath it extends a vast network of limestone caves.
The day before my visit, heavy rain had fallen—enough to close the caves—and it continued to pour on the day itself. The usual route through Akiyoshido Cave begins at the main entrance at the foot of the mountain and ascends through the cave. However, as I was visiting with my three-year-old son, we took the reverse route, descending instead.
As I grew accustomed to the cool air inside the cave, I found myself completely captivated by the forms shaped by nature. Because we were moving against the usual direction, I experienced the cave alongside the flow of water. Rain falling onto the plateau becomes groundwater, seeping from stalactites, pouring down like waterfalls in places, and gradually forming a river within the cave. The formations created by this flow—terraced pools, columnar structures—display an astonishing diversity. At moments, I felt as if this might have been the landscape of the earth before life spread across its surface.
At the same time, I was struck by a feeling close to resignation—how limited the forms we create in architecture truly are. This nearly one-kilometer-long sequence of formations, shaped by dissolving limestone and the force of gravity, seemed to condense within it every kind of terrain one might encounter on earth. Each form carried a monumental beauty.
The sight of raindrops falling onto the plateau, becoming a river within the cave, and eventually flowing outward into a mist-filled forest as a larger current—like a sea—felt like witnessing, in real time, the diagrams of the water cycle we often see illustrated. Above all, I cannot forget the moment of emerging from the darkness of rock and underground water into a world where light and water seemed to explode into life through vegetation.
Still filled with excitement, I later looked into the geology of the karst plateau. Akiyoshidai, it turns out, was once the seabed some 350 million years ago, where coral reefs accumulated before being uplifted to form the plateau. Remarkably, the thickness of this accumulated layer is said to be between 500 and 1,000 meters. What was once ocean floor becomes mountain; what was once surface sinks beneath the sea. The earth’s surface behaves almost like a fluid, continuously deforming in waves.
I recall hearing that even Mount Everest, the highest mountain in the world, was once beneath the sea. From the perspective of the earth, a vertical shift of a few thousand meters may not be extraordinary at all. Standing within such a landscape, one begins to grasp both the smallness of human existence and the fluidity of the planet when considered on a cosmic scale of time and form.
Around the same time, I began using Apple Vision Pro, a device that enables what is called an XR (extended reality) experience—a fusion of the physical and virtual worlds. As a form of spatial computing, it allows digital content to appear directly within the space we physically occupy, experienced simultaneously through a headset. What was once encountered through flat, fixed screens now emerges seamlessly within reality.
Conversely, one might say that we are simply viewing highly digitized representations of real space in a way that feels indistinguishable from reality. In any case, as someone drawn to new technologies, it has become an irresistible tool—one that I immerse myself in whenever time allows.
The world experienced through such technologies and the environment of the earth encountered through one’s own body are both irreplaceable experiences. Yet spatial computing cannot reproduce the immediacy of being there—the sensation of a place received through the entire body as a sensing organ. Visiting Akiyoshidai, I was reminded of the strength, the irreplaceable quality, of experiencing a real place.
At the same time, it feels insufficient to simply assert the uniqueness of physical experience in contrast to technological mediation. This is only an intuition, but I sense that as information technologies such as XR and the internet advance, the sensory capacities through which we perceive real space are themselves being sharpened. At least for me, this is something I feel quite strongly. Perhaps, as we become accustomed to experiencing digitized spaces, we become more attuned to what cannot be digitized—opening our senses more fully, and strengthening our ability to perceive place.
Through such shifts in sensibility, what kind of real spaces will people seek? And what kind of spaces can we, as architects, create?
Recently, I find myself increasingly drawn to rural mountain villages and agricultural landscapes—to architectures shaped by the specific climates and cultures of their regions. The rooftops of settlements in Akiyoshidai, clad in Sekishu tiles, appeared almost seamlessly integrated with the terrain, forming a quiet and compelling unity. In contrast, the more commonly used metal sheet roofing felt, if anything, out of place.
Architecture is built on a given site and, in most cases, remains fixed. Yet perhaps, through a contemporary sensibility, this very immobility will become even more pronounced—leading architecture to be more deeply embedded within the terrain itself.
(Published in Hitotsuchi, “On Tile Architecture,” August 2024)