Sho (a unit of volume in the East Asian system of weights and measures) (升)
Sho is a standard unit of volume (capacity) in the East Asian system of weights and measures. 10 go (合; a unit of volume) is equal to 1 sho, and 10 sho is equal to 1 to (斗; a unit of volume). The volume of 1 sho varies from time to time, from place to place. After the metric system was adopted in Japan, 1 sho was set at 1.8039 liters in 1891. In People's Republic of China, 1 sho (also called as sheng in pinyin) is equalized with 1 liter, and the liter as the unit of the International Unit System (SI) is also written as 'sho' (升) in a Chinese character. To make a simple distinction, the Chinese sho is called sheng (private sho), and the international sho is called kosho (public sho), but usually, they are both simply called sho because they have the same quantity (refer to the article of Shizhi [Chinese System of Measurement]).
Originally, sho was an anthropomorphic unit that represented the quantity scooped up with both hands. At that time, the volume of 1 sho was about 200 milliliters, roughly a 10th of the present 1 sho. As times went by, the size of 1 sho became larger, and at present, the quantity of 1 sho is roughly 10 times the size of the original.
The pictogram of a ladle with something in it became the Chinese character of '升' (sho). Because of this origin, the character 升 came to represent 'masu' (a square, wooden measuring cup), and also sho, which is the unit of the volume measured with the masu, and in addition, it now represents the Japanese verb 'noboru' (means 'rise'), which came from the act of scooping something up with a ladle. In later years, to make a distinction, masu became written as '枡' by attaching the left radical of tree (木) to '升,' but in reality, the distinction between 升 and 枡 seems to have been not so strict. As previously mentioned, the masu was not made to measure the unit of sho, but the 'sho' was defined by the existing masu to measure.
History of sho in Japan
In Japan, the unit of 'sho' was seen for the first time in Taiho Ritsuryo (Taiho Code). In China, 1 sho was roughly the same as today's 1 go in the ancient times, and it became roughly the same as today's 3 go in the age of the Tang Dynasty, and around when the unit was introduced into Japan, it became roughly the same as today's 4 go. Japan introduced the sho of the Tang Dynasty, and established both the unit of daisho (larger sho) that had the volume of about 0.71 liters (about 0.4 size of the new kyomasu [masu mainly used in Kyoto]) and the unit of shomasu (smaller sho) that had the volume of about 0.24 liters (a third of daisho, and about a 10th size of the new kyomasu), a theory says.
Including this, there exist various theories, thought out by scholars in the Edo and other periods, about how much the volume of 1 sho really was in the Nara period, and all of them were just the speculation, merely based on the depiction seen in the penal and administrative law of the period, and on the Chinese system of weights and measures. Exceptionally, however, Goichi SAWADA took a different approach of measuring the size of a granary in the Nara period, and found that 1 koku (a unit) then had 2800 cubic sun (寸; a Japanese traditional unit of length). 1 sho at that time was converted into 0.4 sho with today's standard ("the numerical study of the economy under the civil administration in the Nara period," written by Goichi SAWADA, republished by Kashiwashobo Co., Ltd.). And this is the volume that sho is deemed most trustworthy today.
As Ritsuryo system (the system of the centralized regime based on the ritsuryo code) broke down, local provinces, later, local manors, began to use sho of their own. Emperor Gosanjo enforced the reorganization of manors, and as a part of it, in 1072 he officially established a masu, which would be called Enkyu senji-masu (the standard masu set by the imperial order in the Enkyu era [1069 to 1074]) in later days. The exact volume of this masu is not known, either. Several records have descriptions of the volume, such as, with today's standard, 0.6270 sho (in "Irohajirui-sho" [a dictionary written by Tadakane TACHIBANA in the Heian period]), 0.8223 sho (in "the endorsement of a request about a fief of Moriyoshi AZUMA"), and 0.4932 sho (in "Junhai" [a document in Kamakura period]) (according to "the study of the history of quantitative system in Japanese medieval age," written by Keigo HOGETSU, published by Yoshikawa Kobunkan Inc. in 1961). Hogetsu says 0.6270 sho in "Irohajirui-sho" is most trustworthy. "Junhai," written in the last days of the Kamakura period, says that it was a masu with 4 sun square and 2 sun depth (32 cubic sun) and had 0.81 liters, which was 0.45 times of new kyomasu, however, it is considered to be unreliable since the book says it was made by 'Kanji senji' (the imperial order in Kanji era [1087 to 1094]) which was clearly contrary to the fact that the senji-masu was established in the Enkyu era. However, some scholars adopt the theory of Junhai, saying that the masu in the Kanji era should have restored the ancient system ("the illustrated dictionary of units' history," written by Kesakatsu KOIZUMI, published by Kashiwashobo Co., Ltd.). The Hogetsu's amount of 0.6270 sho is calculated with the standard kane-jaku (a carpenter's iron square) which was used commonly in medieval Japan, however "Irohajirui-sho" was compiled by the late Heian period at the latest when ritsuryo-jaku (the length measure established under the Ritsuryo system) was 0.97 times of the length of the kane-jaku, that is, it was 0.5722 sho in present day. Some documents were written about senji-masu (the standard masu set by the imperial order) from the late Heian period until around the late Kamakura period, in Kyoto, Kanto, and Kyushu regions, but it is not clear to what extent the masu diffused.
From the period of the Northern and Southern Courts, the authorization of senji-masu became rarely done, and instead, local provinces began to use masu of their own. But nevertheless, the energetic commerce naturally demanded the masu that could be commonly used in market. This masu for commerce, called mise-masu or machi-masu, seems to have been a bit smaller than new kyomasu, and to have had the volume similar to old kyomasu (according to the previously mentioned book written by Keigo HOGETSU). According to "Tamonin Nikki" (The Diary compiled from 1478 to 1618 by Eishun and other Buddhist priests at Tamonin Temple), Kofuku-ji Temple officially established the standard masu in Nara, which had about 0.8 time the volume of new kyomasu and functioned in the market. This depiction is just about the then situation in Nara, so it is wrong to think that the situation was the same in Kyoto or other places all over Japan.
When unification of the whole country was in process with the power of Nobunaga ODA and then Hideyoshi TOYOTOMI, there was the need to standardize the masu used nationwide in common, because the standard of the masu (or sho) affected the amount of nengu (land tax) paid by farmers. Nobunaga ODA officially designated the 10 go masu, which was used at that time, as the standard masu for commerce. In 1571, the historical document mentioning 'hansho' (the masu with 'kao' [written seal] of the publisher) appeared for the first time, and thereafter the depiction in the document about the 10 go masu became quite rare, which backs up the previously-mentioned official designation of the masu by Nobunaga. In November 1586, Gengo NAKABO, a local governor dispatched by Hideyoshi TOYOTOMI, prohibited the use of the masu that had been common until then in Nara, and enforced the use of a new masu. This new masu was used mainly in Kyoto at that time, so it was called kyomasu (literally, masu used in Kyoto). This kyomasu is also called old kyomasu in order to differentiate it from the new kyomasu which is mentioned later. Old kyomasu had 5 sun square, 2 sun and 5 bu (1 bu is a tenth of 1 sun) in width, with 62.5 cubic sun, and had the volume of 1.74 liters, that is, 0.964 size of new kyomasu.
In 1669, Edo bakufu (Japanese feudal government headed by a shogun) abolished edo-masu, which was used mainly in Edo and had the same volume as old kyomasu, and enforced the use of new kyomasu, which was a little larger than old kyomasu. The new kyomasu had 4 sun and 9 bu square, 2 sun and 7 bu in depth, and about 1.8039 liters in volume. Edo bakufu, by reducing the length and the width by 1 bu while increasing the depth by 2 bu, wanted to trick the people into believing that the volume did not change, and the bakufu tried to conceal that the volume of the masu in real increased by about 3.7 percents, a theory says. The uniformity of the volume was kept for about 300 years in the Edo period, because Edo bakufu strictly took control of the size of masu through 'masuza' (the masu guild) opened both in Edo and in Kyoto.
1 sho measured with the new kyomasu with square of 49 bu times 27 bu in depth had the volume of 64,827 cubic bu, from 49 times 49 times 27. The number of 64,827 was remembered through its resemblance in Japanese pronunciation to the words "musha-funa" (a crucian carp like a warrior) or "mushi ya funa" (an insect and a crucian carp).
In 1875, the Meiji government designated the new kyomasu as the official masu. In the Weights and Measures Act enacted after the ratification of the treaty of the meter, 1 shaku (a length unit) was set at 10 over 33 meter based on the metric system. 1 bu is a 100th shaku, so the volume of 1 sho is calculated by multiplying 64,827 of cube (10 over 33 times a 100th) times 3, that is, almost equal to 0.0018039 cubic meters, or almost equal to 1.8039 liters. In 1959, the Measurement Act was enforced and the use of units other than the metric system was strictly prohibited, so sho ended in its official use. However, some kinds of alcohol, such as sake (Japanese liquor), are sold by the amount of 1.8 liters even today. In Japan, the glass bottle of the capacity of about 1.8 liters has been called 'Isshobin' (1 sho glass bottle) and it has been used for alcohol, cooking oil, soy sauce, and so on, but today, it tends to be replaced with the plastic bottle of the size other than 1.8 liters, so 1.8 liter glass bottle is, except for that for business use, fading away.
Masu and Japanese culture
As previously mentioned, the Chinese character of '升' has the reading of 'masu,' which is the pronunciation peculiar to Japanese. 5 go is equal to a half of 1 sho (reads as 'hanjo' in Japanese), so Japanese people use this and pose a riddle how to read '2 masu 5 go,' and the answer is 'masu masu hanjo' (means 'more and more prosperous'). On a teacup or something, they often write 'spring, summer, 2 masu 5 go, and winter' (no autumn), and these words read as 'akinai masu masu hanjo' (means 'business prospers more and more'), and the thing with these words is regarded as a good luck charm. 1 to is equal to twice (reads as 'bai' in Japanese) 5 sho (reads as 'go sho' in Japanese), so Japanese people sometimes use this and do a wordplay how to read '1 to, 2 sho, and 5 go,' and the answer is 'goshobai masu masu hanjo' (means 'your business becomes more and more prosperous').