Walls that move
In a traditional Japanese house, many of the walls inside are not walls at all but sliding panels that run in grooves in the floor and the lintel above. The two main kinds are shoji and fusuma. They look quite different and do different jobs, but both let the size, brightness and privacy of a room change within moments.
Shoji: light through paper
A shoji is a sliding frame of thin wooden strips with translucent paper on one side. The grid of strips, which can be simple or intricate, holds the paper flat and gives the panel strength. The paper is traditionally a thin, strong sheet in the family of washi paper, and it diffuses daylight into a soft, even glow rather than letting it pass in a hard beam.
Shoji are most often found on the outer edge of a room, facing the veranda or a garden. They let light in while blocking a direct view, so a person indoors has privacy and still feels the weather and time of day: pale blue in the early morning, bright and even at noon, dim and warm in late afternoon. Shadows of branches or passing people can show faintly on the paper.
The framework is carefully made. The delicate wooden pattern relates to the craft of kumiko lattice, in which small pieces are cut and fitted without nails into decorative designs. Good panels slide smoothly because the wood is dry and the grooves are waxed or smooth, which is a quiet example of the joinery found in Japanese architecture.
Fusuma: opaque, decorated partitions
A fusuma is also a sliding panel, but it is covered on both sides with thicker paper or cloth, so it blocks light and sight. It divides one room from another inside the house. Its surfaces can be plain or decorated, and in grand buildings they carry painted scenes. This tradition connects to sliding door paintings, which formed part of the interiors of castles, temples and noble residences.
Fusuma also close off built-in closets, including the one that holds bedding in the day. Because they are made of paper over a light frame, they are easy to slide and not heavy. A pull recess, a small shaped hollow in the panel, replaces a protruding handle so that the surface stays flat.
Changing a room’s size
The main practical benefit of sliding partitions is that they can be removed. Fusuma and shoji panels can often be lifted out of their tracks and stored, allowing two or three rooms to become one large space for a gathering, a memorial or a festival. Afterward the panels are slid back, and the rooms return to their smaller sizes.
This flexibility is made easier by the modular system of room measurement, in which rooms are sized by the number of tatami mats and the spacing of posts is regular. Panels made to a standard size fit openings throughout the house. The unusual thing, compared with houses with fixed walls, is that the layout is not frozen. A family could plan a room for sleeping at night, dining at midday and entertaining in the evening, and open or close the house to match the season.
Through the day and the year
The effect changes over a day. In the morning, the shoji can be opened to let in air and sunlight. At midday they may be closed partly to soften the light, and at night they are closed, sometimes with wooden storm shutters outside. In cold weather, the panels offer some protection against drafts, though they do not insulate as much as a solid wall, which is one reason traditional houses are often cold in winter. People used warm clothing, quilts and heated tables to cope.
In summer, the panels may be taken out altogether and replaced by blinds or reed screens that let air move through. The house becomes more open. Care of the panels follows a yearly rhythm in many households: paper can tear or yellow, so it is replaced from time to time, and doing so before the New Year is a traditional habit in some places. Modern versions use stronger papers or plastic films for durability, and replacement is a task for which people usually learn from experienced relatives or professionals.
Space, privacy and sound
Paper panels offer visual privacy, but not sound privacy. In a traditional house, people tended to adjust their behavior to the shared space, speaking softly and being aware of each other. The idea of boundaries that are soft rather than absolute is often connected with the concept of ma, in which the interval between things is itself meaningful.
Sliding screens also change the relationship between inside and outside. When the outer panels are open, the garden becomes part of the room, and a view of leaves or a stone lantern appears as a framed scene, echoing garden design that expects to be seen from indoors. Closing the panels returns the room to quiet.
Present-day use
Many modern apartments no longer use these panels, but they remain in traditional homes, inns and temples, and some contemporary interiors borrow the look with panels of glass or acrylic. Whether made of paper or not, the underlying idea persists: a room is a flexible container, and its boundaries can adapt to who is present, what the weather is doing and what the day requires.