The name also appears in the literature as Gangdêz, Gangdiz, Gangdizh, Kangdiz, Kangdizh, Kangdezh, etc.
Among the interpretations of the name are "fortress of youth" from kang "youth" and dêz "fortress, palace." Others relate "kang" or "gang" to the Chinese name for Sogdiana.
Kang/gang has also been suggested as Ganga and thus "Fortress of Ganga," or Gangdizh = Ganga Desha "Land of the Ganges."
According to late Zoroastrian texts, Kangdêz was located beyond Khotan and China, a year's voyage (seven months for Kai Khusrau) to the East by sea from the Baluchi port of Makran.
In the Zend Avesta, the Vourukasha Sea lies in the extreme East from which all waters come with the wind and clouds. It is described as the "deep sea of salt waters." Reference is made to tides, of the "waters rising up and going down" and of a southern sea into which the Vourukasha empties and from which it refills causing the tidal ebb and flow.
In the Vourukasha Sea is Erânvêj, where the peak Hukairya is located. On Hukairya is the world spring and world river known as Ardvi Sura Anahita, the source of water for all the world's rivers, reminiscent of the Abzu and Okeanos. Also on this peak grows the sacred White Haoma.
In latter literature, Siyavush is said to have built Kangdêz on the "frontier" of Erânvêj. In the Vourukasha (Varkash) Sea is also mentioned the giant ox Sarsoak from whose back was taken the three sacred fires including the priestly Farnbag fire which was transported to Khvarizem.
As noted, Muslim geographers identified the Yamakoti of Hindu astronomy, dating to at least the beginning of the 5th century, with Kangdêz as the prime meridian. There may also be a connection with the Avestan idea of the celestial bodies "revolving" over the peak Hukairya i.e. as a prime meridian rather than as a polar mountain as sometimes interpreted.
While the al-Balkhi school used Kangdêz as the prime meridian, others located the fabled location according to Ptolemaic or Indian Ujjain system.
Al-Kashi, for example, in the 15th century places Kangdêz at the extreme East or 180 degrees East longitude, and at the equator (0 degrees latitude). He distinguishes it from Yamakoti (Jamkut) which is located at 176 East, 5 North.
To compare these coordinates with other locations in al-Kashi, Zaiton, the city made famous in Europe by Marco Polo, was placed at 154 East, 18 North. Quanzhou, from which voyages to the medieval kingdom of Sanfotsi embarked, is located at 162 East, 13 North.
Here we can see that al-Kashi's latitudes this far east are depressed south of the correct position.
The fairest spot in this world is Gang-dizh
Where by the Grace of Him Who giveth good
My wisdom and my fortune have not slept,
And I have raised the summit to the Pleiads
--- Shahnama of Firdausi (translated by Arthur George)
The quote above indicates that Kangdêz (Gang-dizh) was also thought by some to be under the Pleiades constellation. Whether this refers to the time of the Shahnama or some earlier generation would make a great difference in calculating what latitude the Pleiades was stationed over at the time.
Legends of Kangdêz appear to have influenced the Shi'ite belief in the Green Island where the 12th "Hidden Imam" waits in eternal youth for the last days. The Green Island is described as located in the midst of a Sea of Whiteness that brings to mind the Indian Milky Ocean and the Vourukasha Sea, that appeared like 'quicksilver.'
Paul Kekai Manansala
Blochmann, M.A. and H. S. Jarrett. The Ain i Akbari by Abul Fazl Allami, Asiatic Society of Bengal, 1873-1907.
Kennedy, E. S. and M. H. Kenneyd. Al-Kashis Geographical Table, DIANE Publishing, 1987.H.
Muller, Max . The Zend Avesta, Kessinger Publishing, 2004.
Warner, Arthur George and Edmond Warner. The Shahnama Of Firdausi, Routledge (UK), 2001.