Shoji

[7] The posts are generally placed one tatami-length (about 1.82 metres (6.0 ft)) apart, and the shoji slide in two parallel wood-groove tracks between them.

[8] In modern construction, the shoji often do not form the exterior surface of the building; they sit inside a sliding glass door or window.

[5] Shoji are valued for not setting a sharp barrier between the interior and the exterior; outside influences such as the swaying silhouettes of trees, or the chorus of frogs, can be appreciated from inside the house.

[4][10] Shoji are also thought to encourage a home's inhabitants to speak and move softly, calmly, and gracefully, an important part of the ethos behind sukiya-zukuri architecture.

[10] Shoji rose in popularity as an integral element of the shoin-zukuri style, which developed in the Kamakura Period (1123–1333), as loss of income forced aristocrats into more modest and restrained architecture.

[11] This style was simplified in teahouse-influenced sukiya-zukuri architecture,[12] and spread to the homes of commoners in the Edo Period (1603–1868), since which shoji have been largely unchanged.

[27][28] Rectangular shoji may skew, in which case bent springs of bamboo are inserted into the short diagonal to push them back square.

[4] Some simple kumiko types include: The lowest portions of the shoji, which are the most likely to get wet[42] or kicked,[41] might be filled with a solid wood-panel dado, called a koshi (腰; literally, waist or hip; not to be confused with kōshi, above).

Now that shoji are rarely exposed to rain (due to being behind glass), the form in common use has a much lower panel, and is called koshi-tsuki-shōji (腰付障子).

[43] Sudare-shōji (簾障子; also called sudo, 簾戸) are filled with Phragmites reed, cat-tail stalks, pampas grass, or fine bamboo, held together by a few rows of thread woven around the stems.

[50] Shoji are most commonly filled with a single sheet of paper, pasted across the back of the frame (on the outer side).

Shoji may also be papered on both sides, which increases thermal insulation and sound absorption; the frame is still visible in silhouette.

[7] Cloth, usually a fine silk, has traditionally been used, but usage declined with improvements in the quality of washi (a specialized paper which diffuses light particularly well, and excludes wind).

Washi was formerly made in narrower strips, which were overlapped by a few millimeters as they were glued on; it now comes in wider widths, and in rolls or lengths the height of a short Japanese door.

Laminated papers, coated in vinyl, last longer and are sufficiently waterproof to be wiped clean, but the thicker the plastic film, the harder it is to install.

[59] Traditionally, abura-shōji (油障子: "oil-shoji"), also called ama-shōji (雨障子: "rain-shoji"), used paper (generally nishi-no-uchigami, 西の内紙) that was glued on with vinegar-based paste and then oiled.

[5][9] This is particularly important in traditional buildings, in which charcoal is burned,[5] and damp evaporates from the ground in the crawlspace under the raised wooden floor.

[10] Less traditionally, rigid light-diffusing panels of plastics are also used,[61] such as approximately 2 mm-thick[62] acrylic[63][64] or polycarbonate[65] which can be frosted or bonded to a printed film.

[73] Nonwoven sheets of composite plastic (vinyl-coated polyester) fibers are also used,[74] and may be attached with removable fasteners rather than glue, although they are still single-use.

[10] The traditional wooden track requires precise fitting,[5] and the wood may wear with use, or warp due to changes in humidity.

[83][84] Small windows and katabiki mounting were used in minka until the mid-Edo period, but were then replaced by larger openings with sliding panels.

[5][85] Less traditionally, hiki (引) shoji (sliding panels) can be hung on rollers, which run on metal rails mounted on the side of the kamoi.

No bottom channel is required or used – panels are typically 16–17 mm thick made from Obeche timber rather than traditional conifer wood.

Literally, shoji means "small obstructing thing" (障子; it might be translated as "screen"), and though this use is now obsolete,[4] shoji was originally used for a variety of sight-obstructing panels, screens, or curtains,[4] many portable,[94] either free-standing or hung from lintels,[95] used to divide the interior space of buildings (see List of partitions of traditional Japanese architecture).

[5] Formerly, the grooves were made by dobumizo (どぶ溝), nailing strips of wood to the kamoi (lintel) and shikii (sill) beams.

[29][91] Lower-class buildings adopted some of the cheaper elements of the Shoin style, where the law permitted it (class-based limitations were not lifted until the Meiji Era, in the late 1800s).

[93][108] To open the building in the morning, each ama-do would be slid along (rotating at corners) to the end of groove, where they were stacked in a box[93] called a to-bukuro[109] (戸袋, とぶくろ: literally, "door-container").

[14] Fires were a major problem in Japanese cities well into the Meiji Period; homes (including their furniture and the standardized architectural modules, such as tatami and hiki-do and even floorboards) were made to be quickly packed up and carried away when fire threatened, leaving only the stripped pillars and roof, which could easily be pulled down by firefighters.

[15] In modern Japan, it is fairly common to have garasu-do (all-glass sliding doors) on the outside of the engawa (veranda under the eaves), and translucent shoji on the inside, especially in cold climates.

[120] The ability to slide the shoji aside, and take them out and put them in a closet, means that living space is more spacious, open, and more connected to the garden outside.