Vietnamese units of measurement

Vietnamese units of measurement ( vi, hệ đo lường Việt Nam) are the largely decimal units of measurement traditionally used in Vietnam until metrication. The base unit of length is the ''thước'' (chữ Nôm: 𡱩; lit. "ruler") or ''xích'' (). Some of the traditional unit names have been repurposed for metric units, such as ''thước'' for the metre, while other traditional names remain in translations of imperial units, such as ''dặm Anh'' for the English mile.

History

Originally, many ''thước'' of varying lengths were in use in Vietnam, each used for different purposes. According to Hoàng Phê (1988), the traditional system of units had at least two ''thước'' of different lengths before 1890, the ''thước ta'' (lit. "our ruler") or ''thước mộc'' ("wooden ruler"), equal to , and the ''thước đo vải'' ("ruler for measuring cloth"), equal to . According to historian Nguyễn Đình Đầu, the ''trường xích'' and ''điền xích'' were both equal to , while according to Phan Thanh Hải, there were three main ''thước'': the ''thước đo vải'', from ; the ''thước đo đất'' ("ruler for measuring land"), at ; and the ''thước mộc'', from .

With French colonization, Cochinchina converted to the metric system, the French standard, while Annam and Tonkin continued to use a ''thước đo đất'' or ''điền xích'' equal to . On June 2, 1897, Indochinese Governor-General Paul Doumer decreed that all the variations of ''thước'' (such as ''thước ta'', ''thước mộc'', and ''điền xích'') would be unified at one ''thước ta'' to , effective January 1, 1898, in Tonkin. Annam retained the old standard for measuring land, so distance and area (such as ''sào'') in Annam were 4.7/4 and (4.7/4)² times the equivalent units in Tonkin, respectively.

Length

The following table lists common units of length in Vietnam in the early 20th century, according to a United Nations Statistical Commission handbook:

Notes:
*The ''thước'' is also called ''thước ta'' to distinguish it from the metre (''thước tây'', lit. "Western ruler"). Other than for measuring length, the ''thước'' is also used for measuring land area (see below).
*According to the UN handbook, some areas unofficially use 1 ''trượng'' = . According to Hoàng Phê (1988), the ''trượng'' has two definitions: 10 Chinese '' chi'' (about 3.33 m) or 4 ''thước mộc'' (about 1.70 m).
*The ''tấc'' is also given as ''túc''. According to the UN handbook, some areas unofficially use 1 ''tấc'' = .

Miscellaneous units:

;''chai vai''
:1 ''chai vai'' =
;''dặm''
:According to Hoàng Phê (1988), 1 ''dặm'' = . According to Vĩnh Cao and Nguyễn Phố (2001), 1 ''dặm'' = ''xích'' (Chinese '' chi'') =
; ''lý'' or ''lí''
:According to Vĩnh Cao and Nguyễn Phố (2001), there are two kinds of ''lý'': 1 ''công lý'' = 1 km = ''xích'', while ''thị lý'' is a traditional unit equal to ''xích''.
;''sải''

Area

The following table lists common units of area in Vietnam in the early 20th century, according to the UN handbook:

Notes:
*Annamite units of area were ()² times those of other areas, due to units of length (''trượng'', ''tấc'', etc.) being times those of other areas, as explained above.
*According to the UN handbook, the ''phân'' is also written ''phấn''.
*The ''sào'' is also given as ''cao''. Tonkin and Annam had different definitions of the ''sào''.

Miscellaneous units:

;''công'' or ''công đất''
:The ''công'', used for surveying forested areas, typically in southwestern Vietnam, was equivalent to .
;''dặm vuông''
:The ''dặm vuông'' measures 1 ''dặm'' × 1 ''dặm''.

Volume

The following table lists common units of volume in Vietnam in the early 20th century, according to the UN handbook and Thiều Chửu:

Additionally:
*1 ''phương'' of husked rice = 13 ''thăng'' or 30 ''bát'' (bowls) in 1804
*1 ''vuông'' of husked rice = 604 gr 50
*1 ''phương'' or ''vuông'' or commonly ''giạ'' = , though it is sometimes given as 1 ''phương'' = ½ ''hộc'' or about 30 L
*During French administration, 1 ''giạ'' was defined as for husked rice but only for some other goods. It was commonly used for measuring rice and salt.
*1 ''túc'' =
*1 ''uyên'' =

The following table lists units of volume in use during French administration in Cochinchina:

Notes:
*Unhusked rice was measured in ''hộc'' while husked rice was measured in ''vuông'' because a ''hộc'' of unhusked rice becomes 1 ''vuông'' after husking.
*1 ''hộc'' of unhusked rice weighs 1 ''tạ''.

Miscellaneous units:
;''thùng''
:In Cochinchina and Cambodia, 1 ''thùng'' (lit. "bucket") = . The ''thùng'' is also given as ''tau''.

Weight

The following table lists common units of weight in Vietnam in the early 20th century:

Notes:
*The ''tấn'' in the context of ship capacity is equal to .
*The ''cân'' (lit. "scale") is also called ''cân ta'' ("our scale") to distinguish it from the kilogram (''cân tây'', "Western scale").
*The ''nén'' is also given in one source as , but this value conflicts with the ''lạng'' from the same source at . The 375-gram value is consistent with the system of units for measuring precious metals.
*The ''đồng'' is also called ''đồng cân'', to distinguish it from monetary uses.
*The French colonial administration defined some additional units for use in trade: ''nén'' = 2 ''thoi'' = 10 ''đính'' = 10 ''lượng''

Units for measuring precious metals:
*The ''lạng'', also called ''cây'' or ''lượng'', is equal to 10 ''chỉ''. 1 cây =
*1 ''chỉ'' =

Miscellaneous units:
;''binh''
*The ''binh'' was equivalent to in Annam.

Time

;''canh'' (更)
:The ''canh'' or ''trống canh'' is equal to .
;''giờ''
:The ''giờ'', ''giờ đồng hồ'', or ''tiếng đồng hồ'' is equal to .

Currency

Traditionally, the basic units of Vietnamese currency were ''quan'' (貫, ''quán''), ''tiền'', and '' đồng''. One ''quan'' was 10 ''tiền'', and one ''tiền'' was between 50 and 100 ''đồng'', depending on the time period.

*From the reign of Emperor Trần Thái Tông onward, 1 ''tiền'' was 69 ''đồng'' in ordinary commercial transactions but 1 ''tiền'' was 70 ''đồng'' for official transactions.
*From the reign of Emperor Lê Lợi, 1 ''tiền'' was decreed to be 50 ''đồng''.
*During the Northern and Southern dynasties period, beginning in 1528, coins were reduced from to in diameter and diluted with zinc and iron. The smaller coinage was called ''tiền gián'' or ''sử tiền'', in contrast to the larger ''tiền quý'' (literally, "valuable cash") or ''cổ tiền''. One ''quan tiền quý'' was equivalent to 600 ''đồng'', while 1 ''quan tiền gián'' was only 360 ''đồng''.
*During the Later Lê dynasty, 1 ''tiền'' was 60 ''đồng''; therefore, 600 ''đồng'' was 1 ''quan''.
*During the Yuan dynasty, Vietnamese traders at the border with China used the rate 1 ''tiền'' to 67 ''đồng''.
*Zinc coins began to appear in Dai Viet during the 18th century. One copper (''đồng'') coin was worth 3 zinc (''kẽm'') coins.
*Beginning with the reign of Emperor Gia Long, both copper and zinc coins were in use. Originally the two coins had equal value, but eventually a copper coin rose to double the worth of a zinc coin, then triple, then sixfold, until the reign of Emperor Thành Thái, it was worth ten times a zinc coin.

Under French colonial rule, Vietnam used the units ''hào'', ''xu'', ''chinh'', and ''cắc''. After independence, Vietnam used ''đồng'', ''hào'', and ''xu'', with 1 ''đồng'' equaling 10 ''hào'' or 100 ''xu''. After the Vietnam War, chronic inflation caused both subdivisions to fall out of use, leaving ''đồng'' as the only unit of currency. However, Overseas Vietnamese communities continue to use ''hào'' and ''xu'' to refer to the tenth and hundredth denominations, respectively, of a foreign currency, such as ''xu'' for the American cent.

See also

*Heavenly Stems & Earthly Branches
*Units, Systems, & History of measurement
*Chinese, Taiwanese, Hong Kong, Japanese, Mongolian & Korean units of measurement

References

{{Vietnam topics

Customary units of measurement
Science and technology in Vietnam
Systems of units
History of Vietnam
Units of measurement by country