A seal, in an East and Southeast Asian context, is a general name for printing stamps and impressions thereof which are used in lieu of signatures in personal documents, office paperwork, contracts, art, or any item requiring acknowledgement or authorship. In the western world they were traditionally known by traders as chop marks or simply chops. The process started in China and soon spread across East Asia. China, Japan and Korea currently use a mixture of seals and hand signatures, and, increasingly, electronic signatures.
Chinese seals are typically made of stone, sometimes of metals, wood, bamboo, plastic, or ivory, and are typically used with red ink or cinnabar paste (Chinese: 朱砂 ; pinyin: zhūshā ). The word 印 ("yìn" in Mandarin, "in" in Japanese and Korean) specifically refers to the imprint created by the seal, as well as appearing in combination with other morphemes in words related to any printing, as in the word "印刷", "printing", pronounced "yìnshuā" in Mandarin, "insatsu" in Japanese. The colloquial name chop, when referring to these kinds of seals, was adapted from the Hindi word chapa and from the Malay word cap, meaning stamp or rubber stamps. In Japan, seals (hanko) have historically been used to identify individuals involved in government and trading from ancient times. The Japanese emperors, shōguns, and samurai each had their own personal seal pressed onto edicts and other public documents to show authenticity and authority. Even today Japanese citizens' companies regularly use name seals for the signing of a contract and other important paperwork.
The Chinese emperors, their families and officials used large seals known as xǐ (璽 ), later renamed bǎo (寶 ; 'treasure'), which corresponds to the Great Seals of Western countries. These were usually made of jade (although hard wood or precious metal could also be used), and were originally square in shape. They were changed to a rectangular form during the Song dynasty, but reverted to square during the Qing dynasty.