The concept of 盖章 is deeply rooted in Chinese history and represents a different understanding of authority and identity compared to the West.
In Western cultures, particularly American culture, a handwritten signature is the ultimate mark of personal agreement and identity. Its uniqueness is its strength. In China, while signatures (签名, qiānmíng) are used, the ultimate symbol of official authority and authenticity belongs to the seal (印章, yìnzhāng).
The Seal as the Authority: A company's official seal (公章, gōngzhāng) is a physical object that embodies the company's legal identity. Whoever holds the seal can, in theory, approve documents on behalf of the company. This is why control of the company seal is a major issue in Chinese business disputes. The power is vested in the object, not just the person.
Comparison to a Signature: A Westerner might sign a contract to make it valid. In China, that same contract would almost certainly require the company's red seal to be stamped on it. The signature of the CEO might be there, but the 盖章 is often the legally decisive action. It's less about individual assent (“I agree”) and more about official, institutional validation (“This is officially approved”). This reflects a cultural value placed on collective and institutional authority over individual authority.