"In order that the precise time of sowing and harvesting might be known and that nothing might be lost, the Inca caused four poles to be set up on a high mountain east of Cuzco, about two varas apart, on the heads of which there were holes, by which the sun entered, in the manner of a watch or astrolabe.

Observing where the sun struck the ground through these holes, at the time of sowing and harvest, marks were made on the ground.

Other poles were set up in the part corresponding to the west of Cuzco, for the time of harvesting the maize.

Having fixed positions exactly by these poles, they built columns of stone for perpetuity in their places, of the height of the poles and with holes in like places.

All round it was ordered that the ground should be paved; and on the stones certain lines were drawn, conforming to the movements of the sun entering through the holes in the columns.

Thus the whole became an instrument serving for an annual time-piece, by which the times of sowing and harvesting were regulated. Person were appointed to observe these watches, and to notify to the people the times they indicated."

Sarmiento de Gamboa

Notes from the translator, Sir Clements Markham:

"The pillars at Cuzco to determine the time of the solstices were called Sucana. The two pillars denoting the beginning of winter, whence the year was measured, were called Pucuy Sucanca. Those notifying the beginning of spring were Chirao Sucana. Suca means ridge or furrow and sucani to make ridges: hence sucana, the alternate light and shadow, appearing like furrows.

Acosta says there was a pillar for each month.

Garcilasso de la Vega tells us that there were eight on the east, and eight on the west side of Cuzco in double rows, four and four, two small between high ones, 20 feet apart.

Cieza de Leon says that they were in the Carmenca suburb.

To ascertain the time of the exuinoxes there was a stone column in the open space before the temple of the Sun in the centre of a large cirle. This was the Intihuatana. A line was drawn across from east to west and they watched when the shadow of the pillar was on the line from sunrise to sunset and there was no shadow at noon.

There is another Intihualana at Pisac, and another at Hatun-Colla. Inti, the Sun God, huatani, to seize, to tie round, Intihuatana, a sun circle."

Source: History of the Incas, page 86