Yojana

A yojana (Devanagari: योजन; Khmer language: យោជន៍; โยชน์; ယူဇနာ) is a measure of distance that was used in ancient India, Cambodia, Thailand and Myanmar. Various textual sources from ancient India defines Yojana as ranging from 3.5 to 15 km.

Edicts of Ashoka (3rd century BCE)
Ashoka, in his Major Rock Edict No.13, gives a distance of 600 yojanas between the Maurya empire, and "where the Yona king named Antiyoga (is ruling)", identified as King Antiochus II Theos, whose capital was Babylon. A range of estimates, for the length of a yojana, based on the ~2,000 km from Baghdad to Kandahar, on the eastern border of the empire, to the ~4,000 km to the Capital at Patna, have been offered by historians.

"....And this (conquest) has been won repeatedly by Devanampriya both [here] and among all (his) borderers, even as far as at (the distance of) six hundred yojanas where the Yona king named Antiyoga (is ruling), and beyond this Antiyoga, (where) four kings (are ruling), (viz, the king) named Tulamaya, (the king) named Antekina, (the king) named Maka, (and the king) named Alikyashudala, (and) likewise towards the south, (where) the Cholas and Pandyas (are ruling), as far as Tamraparni."

Units
In Hindu scriptures, Paramāṇu is the fundamental particle and smallest unit of length.

Variations in length
The length of the yojana varies depending on the different standards adopted by different Indian astronomers. In the Surya Siddhanta (late 4th-century CE–early 5th-century CE), for example, a yojana was equivalent to 5 mi, and the same was true for Aryabhata's Aryabhatiya (499). However, 14th-century mathematician Paramesvara defined the yojana to be about 1.5 times larger, equivalent to about 8 mi. A. C. Bhaktivedanta Swami Prabhupada gives the equivalent length of a yojana as about 8 mi throughout his translations of the Bhagavata Purana. In The Ancient Geography of India, Alexander Cunningham says that a yojana is traditionally held to be between 8 and 9 miles and calculates by comparison with Chinese units of length that it could have been between 6.7 mi and 8.2 mi.