In tatamiwari, a way of planning a traditional Japanese house, rooms are laid out from the size of the tatami mat. The kyōma mat measures 6 shaku 3 sun by 3 shaku 1.5 sun, about 1.91 by 0.955 meters. The smaller inakama mat is generally about 1.76 by 0.88 meters, although sources give different figures.
Kiwari
Kiwari sets the proportions of the parts of a traditional Japanese building, the size of each member relative to the others. Shōmei, a manual of the Heinouchi family, master carpenters to the shogunate, records the kiwari for gates, shrines, Buddhist temples, pagodas and buildings in the shoin style. It is dated 1608.
JIS
Japan’s national standards for products are JIS, the Japanese Industrial Standards. The law behind them provides both for setting the standards and for running the JIS mark system.
On July 1, 2019, a revision of that law took full effect. It changed the Japanese name of JIS from Nihon Kōgyō Kikaku to Nihon Sangyō Kikaku, from industrial standards to standards for industry as a whole.
B Sizes
Japanese paper comes in A and B sizes. The standard JIS P 0138 defines a B series of its own, separate from the ISO B series. JIS B0 measures 1,030 by 1,456 millimeters, ISO B0 1,000 by 1,414. In Japan, paper in the B series follows the JIS sizes more commonly than the ISO sizes.
Tactile Paving
Japan laid its first tactile paving blocks, tenji burokku, in 1967. Over about twenty years, they spread to railways, roads and public buildings. Blocks laid in those years came in many shapes and sizes.
In 2001, the standard JIS T 9251 unified the shape and size of their raised dots and bars.
Ten Cards, One Network
On March 23, 2013, Japan’s railway IC cards began to work on one another’s networks across the country. Ten cards took part: Kitaca, PASMO, Suica, manaca, TOICA, PiTaPa, ICOCA, Hayakaken, nimoca and SUGOCA.
Clear Bottles
In 1992, voluntary design guidelines for PET bottles were set in Japan, so that bottles could be recycled. They call for transparent bottles. A design certification standard for soft drink PET bottles, cited in a 2026 committee document of the Ministry of Economy, Trade and Industry and the Ministry of the Environment, puts it in a few words: chakushoku wa shinai koto, do not color.
Fifty and Sixty Hertz
The Tokyo area runs on electricity at 50 hertz, and the Osaka area at 60. The split goes back to the late Meiji era. Tokyo Electric Light bought 50-hertz generators from Germany, and Osaka Electric Light bought 60-hertz generators from the United States. That difference remains today.
Plarail
Plarail, the toy railway of Takara Tomy, goes back to a plastic train and rail set sold in 1959, when toys of metal and wood were the norm. In 2018, the company said that its rail standard had not changed in 59 years. Rails from that time can still be joined to the newest ones.
Unit Bath
For the 1964 Tokyo Olympics, the Hotel New Otani, Japan’s first high-rise hotel, needed a great many bathrooms in a short time. In 1963, TOTO developed the industry’s first unit bathroom method for it.
Unit baths are now named by size. A 1616 measures 1,600 by 1,600 millimeters inside. Common sizes include 1216, 1317, 1416, 1418, 1618 and 1818.