Koi-Krylgan-kala

Why this is extraordinary

Koi-Krylgan-kala was found in 1938 in the Khorezm oasis, a round building where a canal had run. The central structure is about 44.5 metres across and was about 9.5 metres high, with an outer wall on the order of 7 metres thick and rooms between the core and that wall. The usual history is two lives. A lower period of the 4th to 3rd centuries BC, then a break, then a reuse from about the 1st century BC or the 1st century AD into the 3rd or 4th century AD. An architectural critique has also put the foundation in the 2nd century BC rather than the 4th. The excavation report read the early building as a fortified temple-tomb, a place of burial for rulers, where the sky was watched. The photograph is the round plan that reading depends on: a core, a ring of rooms, and the outer ground cut by the dig.

The sky reading has a number, and the number has been replaced. An earlier study took the main axis at 69 degrees. That was read as sunrise in the middle of the stretch between the spring equinox and the summer solstice, when the sun’s declination is about 15.5 degrees, and also as the heliacal rising of Fomalhaut, the star’s first dawn appearance, around 4 May in the 4th century BC. The third flood of the Amu Darya was placed in mid-May. A star that rises about a week and a half before a flood can be a warning to people who irrigate. The same account tied the rising to a festival, Ajghar. A medieval calendar written down in the early 11th century says the 15th is called Ajghar, “the firewood and the flame,” the season when people began to need fire because the air was changing, and that from that day they counted 70 days and then sowed autumn wheat. The writer says that in antiquity the feast fell in autumn, and that in his own time it fell in midsummer, because the calendar had drifted. Windows of the ground floor did not face equinox sunrise. A diagonal stair, about 21 degrees off the main axis, was offered as the place from which equinox sunrise and sunset could be seen, if you used the stair and the axis together.

A later comparison of the plans with satellite images moved the axis. The line through the long rooms on the main axis measures about 80 degrees, not 69. The difference is put down to magnetic north left uncorrected on the old plans. Magnetic declination in the years of the expedition was about 5 degrees, and the residuals of many Khorezm plans are lopsided in that direction. At 80 degrees the sun rises on the line twice a year, about 12 April and about 10 September. Mid-April is the second flood of the river, the flood of the white fish, not the third. About 10 September sits near the autumn firewood feast in the medieval calendar’s antique timing. Fomalhaut does not rise on an 80-degree axis. Aldebaran rises around 9 June near 81 degrees, and Procyon around 23 July near 82, and those mornings are not the flood and not the feast. The 69-degree sky and the 80-degree sky are two published instruments. Only one of them can be the building.

An architectural study takes a third road. The ground-floor plan is not a cross inscribed in a circle, the shape that had been compared with steppe mausoleums. It is a comb of rooms, a plan used for barracks and stores. A well on the west side, read as a water cult, is read there as a siege supply. The upper storey, read as a funeral pyre and then a temple, is read as a wooden residence that burned. The openings that were used as sightlines are read as air vents, badly placed for watching a horizon. The observatory, in that argument, is a refinement added to a tomb story that the plan does not require. How you would observe the 80-degree sunrise is to stand on the axis and look at the horizon on 12 April or 10 September. Whether anyone did is the part the vents and the tombs are still arguing.