Encyclopedia of the Incas

The trial and error technique is perhaps not very convincing if one considers
megalithic building blocks weighing several dozen tons. Nevertheless, it works
and does not postulate the use of tools and machinery of which no traces have
been found. The Incas had plenty of time and manpower at hand. Since they
moved huge blocks over many kilometers, it is not inconceivable that they were
capable of setting up a stone several times to achieve the desired fit.
It is, of course, also conceivable that the Inca stonemasons knew of another
technique to transfer the shape of one stone to another without actually trying it
in successive steps. Architect Vincent Lee has in fact proposed such a technique.
Inspired by log cabin builders, Lee suggests that the shape of one stone was
scribed onto the other with an ingenious but simple device consisting of a stick
and a plumb bob. Although experiments have shown the technique to work,
there is as yet no evidence that the Incas actually used it.
The Incas often had several construction crews working simultaneously and
side-by-side on the same wall. Where two crews met in a course, the final gap
was closed with a “wedge” stone introduced into the masonry bond from the
front of the wall. Wedge stones fit to their neighbors only along a very narrow
band near the face of the wall and slightly overlap the neighboring stones. Once
one knows what to look for, it is relatively easy to spot wedge stones in an Inca
cut-stone wall and to determine the construction sequences.
How did the Incas transport and heave enormous building stones? Evoking
bas-reliefs discovered at Nineveh in Iraq and el-Bersheh in Egypt that depict
people hauling colossal statues, some have suggested that the Incas may have
moved their big stones on rollers, on sleds, or with both. The Near Eastern bas-
reliefs show large numbers of people pulling the statues with ropes attached to
the statues or to the sled.
Excavations under abandoned blocks near Ollantaytambo failed to prove the
use of either rollers or sleds; they suggest, rather, that the blocks were dragged
on a prepared roadbed. Such roadbeds can still be observed all the way from the
quarries of Kachiqhata to Ollantaytambo’s Temple Hill. Rough abrasion marks
found on many rhyolite building blocks at Ollantaytambo confirm that the stones
were dragged along the ground. From these marks it is even possible to
determine the direction in which the blocks traveled. The dragging of big stones
is consistent with chroniclers’ reports, such as this one by Pedro Gutiérrez de
Santa Clara: “These Indians used to move very large stones with muscle power,
pulling them with many long ropes of lianas and leaf fibers . . . and they [the
stones] are so big that fifteen yokes of oxen could not pull them” (Gutiérrez de