An inkan or hanko is a name seal customarily used in Japan instead signatures when doing business or other procedures, both for businesses and for private persons. In fact, in certain cases only seals are acceptable.
There are two kinds of seal: mitome-in (personal seal) and the jitsu-in (registered seal).
One needs a registered seal to open an account in some banks or to purchase land or a car.
In modern Japan most people have several; men's are generally larger than women's, and high-ranked executives generally have larger hanko than their subordinates. The most secure forms of hanko are used for banking and real estate deals, while off-the-shelf varieties are used for everyday tasks such as signing for delivery of packages.
Registration and certification of an inkan may be performed in a local municipal office (City Hall). A person receives the "certificate of seal impression" (inkan-toroku-shomeisho, or inkan techo), or the certificate of authenticity, required when performing a business of significance, e.g., when purchasing a car.
Foreigners who have a valid alien registration card are eligible for the name seal, necessary to perform business. Foreign names may be carved in romaji, katakana, hiragana or kanji. Inkans for standard Japanese names may be purchased prefabricated.
Traditionally inkans are engraved on the end of a stick of hard wood, bone or ivory, with a diameter between 25 and 75 mm. Carving them is a kind of calligraphical art. Rubber stamps are unacceptable for business.
The first evidence of writing in Japan is a hanko dating from 57 AD, made of solid gold and belonging to the Emperor. At first only the Emperor and his most trusted vassals held hanko; they were a symbol of the Emperor's authority. Noblemen began using their own personal hanko after 750, and Samurai began using them sometime in the Middle Ages; Samurai were permitted exclusive use of red ink. After modernization began in 1870, hanko finally came into general usage throughout Japanese society.
The increasing ease with which modern technology allows hanko fraud is beginning to cause some concern that the system will not be able to survive for much longer.
Signature stamps are still used widely in cultures outside of Japan. For instance, some Israeli companies still require stamps on official documents. Some say the relative size of the stamps reflects the rank of the officers within the corporation.
Information from: www.indopedia.org