Tan

JapaneseTraditional unit (still used in some regions)

300 tsubo (about 991.74 m²), about a quarter of an acre. A traditional measure of farmland.

1 tan = 991.7355372 square meters (approximately).

About the tan

Rice paddies were counted in tan. One tan is 300 tsubo, or exactly 120,000/121 square metres, about 991.7, which is slightly less than a quarter of an acre. It equals ten se, and ten tan make a cho, so a farmer with several tan had a modest holding by the standards of the tax registers.

The unit belongs to the same system that valued land in koku of rice. Under the Tokugawa shogunate the kokudaka assessed a plot by its yield, and surveyed land was recorded in these agricultural areas. A common claim that one tan was the area needed to grow one koku is not confirmed by the sources consulted, so it should be taken as a rough tradition.

Japan signed the Metre Convention in 1885 and the 1891 weights and measures law gave the traditional units fixed metric equivalents. The Measurements Law of 1951 moved the country to metric units from 1959, and the tan survives mainly in rural land transactions and in talk of rice farming.

Sources: Wikipedia: Japanese units of measurement; Wikipedia: Kokudaka; Wikipedia: Koku

Tan conversion chart

1 tan expressed in every other area unit:

More Japanese units

• jō (tatami mat) (area)
• tsubo (area)
• se (area)
• chō (area) (area)
• sun (length)
• shaku (length)
• ken (length)
• jō (length)
• chō (length)
• ri (Japanese) (length)
• monme (weight & mass)
• kin (weight & mass)
• kan (weight & mass)
• gō (volume)
• shō (volume)
• tō (volume)

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