During the Kot Diji phase, sign use on pottery and other media expanded and began appearing on seals, setting the immediate groundwork for the standardized seal-and-inscription practices of the Mature Harappan period.
Across a wide territory, settlements became more materially standardized (urban layouts, craft products, and administrative artifacts), marking the Mature Harappan horizon in which seals, sealings, and metrology supported large-scale coordination.
By the start of the Mature Harappan period, the Indus script is attested in its developed form, especially on square stamp seals; inscriptions are typically short (often around five signs), suiting labeling/authorization needs rather than long narrative texts.
Square stamp seals—commonly of steatite and bearing animal motifs plus short inscriptions—spread widely in Mature Harappan contexts, implying routinized use of emblem-and-text combinations for identity, authority, or institutional marking.
Cubical stone weights in graduated sizes followed a shared Harappan standard described as a binary system (with larger decimal-scale multiples), enabling consistent valuation and exchange across settlements and reinforcing administrative control over trade.
Although Indus excavations often yield many more seals than sealings, recovered sealings show practical use on containers/bundles and are interpreted as evidence for local management of goods—authorization, accountability, and controlled access—rather than only shipment security.
At Lothal, a distinctive cluster of fired clay sealings (about 70) was recovered from a small area within/near the warehouse passages, supporting interpretations of sealings as temporarily archived control documents tied to storerooms and sealed containers (doors, boxes, jars, bags).
Some Harappan sealings preserve impressions from more than one seal, implying procedures that could require multiple approvals or roles (e.g., shared responsibility for opening/closing, verification, or staged processing of goods).
At Dholavira, a large “signboard” near the northern gateway displayed ten large Indus symbols (made with gypsum pieces on a wooden backing). Its scale and placement suggest public-facing writing used for civic/administrative signaling during the Mature Harappan occupation.
An Indus-style seal impression from Umma in Mesopotamia preserves a sealing practice typical of West Asian jar/cord closures and is used to discuss how Indus seals could be deployed outside South Asia within local administrative conventions for shipments and storage control.
Researchers highlight a notable pattern: Indus sites often show many more seals than clay sealings (reported as roughly 10:1 in some discussions), unlike many West Asian contexts—an imbalance that shapes current interpretations of how seals functioned in Indus administration.
Around the close of the Mature Harappan period, many regions experienced major transformations and discontinuities in material culture and urban systems; post-1900 BCE phases (e.g., Jhukar in Sindh) show continuity alongside change in traditions once supported by Mature Harappan administrative standardization.
Michael CarricoSealings, Tokens and Administrative Practices in the Mature Harappan (c. 2600–1900 BCE)