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Standardizing an Empire

Standardizing an Empire

The intricacy of an ancient record-keeping method called a khipu, is capable of representing the precision of  the International System of Units (SI).

Map of Tawantinsuyu
Figure 1: Map of Tawantinsuyu
Credit: Dumbarton Oaks Museum

Five hundred years ago, how would you keep track of 12 million people spread across some 5,000 kilometers? How would you manage labor or taxation? How would you organize a network of infrastructure, or a capital city? The Inka Empire accomplished all of this with the aid of a brilliant tool: the khipu (or quipu).

Rising to power from 1450-1534 CE, the Andean Empire’s control spanned from present-day Ecuador down to what is now Chile. Known as Tawantinsuyu, or “the four parts together”, the Inka Empire was divided into four regions [Figure 1]. 

Though the Inka have many accomplishments, they are perhaps best known for their impressive engineering. The Inka Road, or Qhapaq Ñan, was the artery of the Empire and allowed for extensive communication and oversight across all four suyus (regions) from Cusco, its capital. Messages, labor, and supplies were sent across the Empire efficiently and easily using these networks. 

Unlike other contemporaneous states and empires, the Inka did not employ a conventional writing system. Instead, the Inka used khipu, a form of record-keeping using colored cords and knots, which was compared to books by Spanish chroniclers at the time.

What is a khipu?

Diagram of khipu structure.
Figure 2: Diagram of khipu structure.
Credit: Jeffrey C. Splitstoser

Khipu–meaning “knot” in Quechua–were created from cords typically made of cotton, llama or alpaca fiber. The cords are arranged in a standard structure, consisting of a primary cord that has smaller pendant cords hanging off it. These pendant cords also can have additional cords attached to them called subsidiary cords. There can also be cords which hang in the opposite direction of the pendant cords, called top or summation cords [Figure 2]. It is the pendant cords, subsidiary cords, and top cords that usually contain the knots, though primary cords can contain knots as well. 

The primary cord typically begins with a loop, a knot, or a special bundle called a kayte, with the opposite end trailing off in a long tail that usually does not have any pendant cords attached, sometimes called the “dangle end”. Kayte are thought to indicate the genre of material in a khipu. Scholars “read” the khipu starting from the kayte / loop end and move until they reach the dangle end. The Inka used a base-ten number system, which the knots on the khipu follow, spaced as if each row across the pendant cords of the khipu represents a different decimal place [Figure 3].

Khipu knot decimal positions.
Figure 3: Khipu knot decimal positions.
Credit: Jeffrey C. Splitstoser

Encoding the Khipu

There are many more ways to encode information in a khipu beyond simply tying knots, including the direction the knots are tied with an S or Z twist, the direction of the ply of the cords (S or Z twist), and the ways that the cords are attached to each other (recto or verso) [Figure 4]. 

The colors of khipu cords –and whether a cord is patterned (barber pole, mottled, monochrome, or segmented)– is likely an important source of significance as well [Figure 5].

Some khipu even have patterns across multiple cords (banding or seriation) [Figure 6]. Scholars study all these components to try and gather more meaning from khipu.

Types of khipu cord attachments, cord twists, and knot twists.
Figure 4: Types of khipu cord attachments, cord twists, and knot twists.
Credit: Jeffrey C. Splitstoser
Khipu cord color types.
Figure 5: Khipu cord color types.
Credit: Jeffrey C. Splitstoser
Seriated and Banded khipu samples.
Figure 6: Seriated and Banded khipu samples.
Credit: Jeffrey C. Splitstoser

Inka Khipu Replica

This cotton Inka khipu displays many elements of signification. The primary cord is mottled and begins with a small kayte, perhaps signaling the khipu genre. Individual pendant cords are either mottled, barber poled, or monochrome, but overall form color bands. This khipu also has a beautiful variety of colors, including green, which is less common than whites or browns. Given the kinks in some of the pendant cords, it appears that some of the knots on this khipu have previously been untied.

Inka Khipu Replica
Inka khipu replica made by Jeffrey C. Splitstoser.
Credit: Photo: Sarah Reeves/NIST Museum
Inka khipu replica detail of top.
Inka khipu replica detail of top. Made by Jeffrey C. Splitstoser.
Credit: Photo: Sarah Reeves/NIST Museum
Inka khipu replica bottom detail.
Inka khipu replica detail of bottom. Made by Jeffrey C. Splitstoser.
Credit: Photo: Sarah Reeves/NIST Museum
 

Khipu Uses

Khipu were used throughout the Inka Empire, typically by khipukamayuqs (“knot makers”). These khipukamayuqs were responsible for the recording and reading of khipu, and employed these devices to keep the Empire running. The khipu were used to record many different types of information–which have been documented by several Spanish chroniclers during the colonial period–such as census data, tributary accounting, resource inventory, and perhaps even histories and lyrical narratives. Khipu could even be wrapped into small portable bundles and carried across the empire by official messengers, or chaskis. In the 17th century, Guaman Poma de Ayala, an Indigenous chronicler from colonial Peru, depicted both khipukamayuqs and chaskis in his drawings [Figure 7 & Figure 8].

Drawing of khipukamayuq by Guaman Poma, 17th-century.
Figure 7: Drawing of khipukamayuq by Guaman Poma, 17th-century.
Credit: Dumbarton Oaks Museum
Drawing of chakis by Guaman Poma, 17th-century.
Figure 8: Drawing of chakis by Guaman Poma, 17th-century.
Credit: Dumbarton Oaks Museum

International System of Units (SI) Khipu

Outer circle has one wedge for each of the 7 SI units (kilogram, meter, second, ampere, kelvin, mole, and candela) and the inner circle has wedges for the 7 important constants.
Download the image files for this logo.
Credit: BIPM

The seven units of the International System of Units (SI), also known as the metric system, are represented on the SI khipu. The SI Khipu was created by George Washington University archaeologist Jeffrey Splitstoser.

SI Khipu
SI Khipu made by Jeffrey C. Splitstoser.
Credit: Photo: Sarah Reeves/NIST Museum
Primary cord detail of SI Khipu
 Primary cord detail of SI Khipu made by Jeffrey C. Splitstoser.
Credit: Photo: Sarah Reeves/NIST Museum
SI Khipu detail.
SI Khipu made by Jeffrey C. Splitstoser detail.
Credit: Photo: Sarah Reeves/NIST Museum
 
 
SI Khipu Diagram Key
SI Khipu Diagram Key
Credit: Jeffrey C. Splitstoser

This object transcends Inka conventions of khipu making to creatively represent these units of measurement in several ways, including the use of wrapped colors to indicate which pendant cord represents which SI unit; the representation of decimals; a signifier for zero; and a knot type to indicate the integer powers of ten.

The primary cord is also barber poled with the seven colors associated with the seven SI units. 

Each SI pendent cord is detailed in the diagrams below:

Kilogram (kg) Khipu
Kilogram (kg) Khipu
Credit: Jeffrey C. Splitstoser
Meter (m) Khipu
Meter (m) Khipu
Credit: Jeffrey C. Splitstoser
Second (s) Khipu
Second (s) Khipu
Credit: Jeffrey C. Splitstoser
Ampere(A) Khipu
Ampere (A) Khipu
Credit: Jeffrey C. Splitstoser
Kelvin (K) Khipu
Kelvin (K) Khipu
Credit: Jeffrey C. Splitstoser
Mole (mol) Khipu
Mole (mol) Khipu
Credit: Jeffrey C. Splitstoser
 
Candela (cd) Khipu
Candela (cd) Khipu
Credit: Jeffrey C. Splitstoser
 
 
 
 

Visit the ‘Defining the International System of Units (SI)’ exhibit online or in NIST Museum for the definitions of each unit.

This exhibit is a collaboration with the Dumbarton Oaks Museum and the Association of NIST Hispanic Americans.

Example of how to reference this exhibit:
NIST Museum. 2023. Standardizing an Empire. Gaithersburg, MD: National Institute of Standards and Technology. Online. https://www.nist.gov/nist-museum/standardizing-empire

Author. Year. Exhibit Name. Place published: Publisher. Online. URL.

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Created September 29, 2023, Updated October 11, 2023