Who are you?

In the West, this is a reasonably simple question to answer. You are who you say you are, and you confirm your identity by signing your name. In Japan, as in many Asian countries which have come under Chinese influence, and as in the West until a few hundred years ago, you confirm your identity with a seal. This seal (hanko) is made of wood or plastic or stone (they used to be made of ivory, and some still are). Since the ivory trade is illegal, the ivory used for these seals is supposedly antique and taken from elephants which have long since gone to meet the Great Tusker in the Sky. The seal is engraved with your family name in Chinese characters (typically, Japanese names are made up of two Chinese characters or kanji, though they may be only one or sometimes three).

This can lead to a very peculiar (to Western eyes) sense of self and responsibility, as I explain here.

The theory and the practice of sealsmanship

In theory, this system is good, though liable to some abuse, such as forgery or unauthorised borrowing of seals. In practice, it's a mess. It's not enough for a Japanese person to have just one seal; most people have at least two or three.

For instance:

a "best" seal, officially registered with the town hall, which is used on legal documents, such as land purchases, company registration, etc. This registered seal is known as an inkan.

a "second-best" seal, used for banking business (even though personal cheques are unknown in Japan, there is a lot of paperwork which must be authenticated).

an "everyday" seal, used for the receipt of registered packages and so on

an "office" seal, used at the office to sign memos, etc.

This, while not quite a reason for an identity crisis, weakens the sense of self that is generated by the development and constant use of a personal signature. When it is possible to buy an "off-the-peg" seal with your name on it, it is very difficult to feel a sense of distinctness from all the other 500,000 Watanabes out there (only the family name appears on a seal, and though the best inkan may well be hand-carved, the everyday seals are bought ready-made from stationers, at least for more common family names).

Even I, as a non-Japanese (and have little legal status here, not having a family registry, etc.), own three seals, which are used regularly. Here are my "everyday" seal (left) and that of my wife (right):

These seals are actually about 1 cm in diameter, plastic, self-inking and housed in a tube a little like a lipstick. Since I cannot write my name in Chinese characters, my name is written in katakana, one of the Japanese phonetic alphabets. My wife's family name literally means "west tail". If you play Mah-Jongg, you'll recognise the top character of her name.

Are you a person or a company?

Again, a reasonably simple question to answer in the West. The laws and customs on limited liability are pretty straightforward, and differentiate clearly between those acts performed as an individual, and those performed as an officer of a company. In Japan, the line between a company and its servants is blurred, and individuals are often held morally responsible, if not always in law, for the debts and obligations incurred by their companies. Likewise, a company feels responsible for the actions performed by its employees, even when they are not undertaken as employees.
Interesting footnote: when Japanese talk in English about the employees of a company, they tend to use the word "member", as if a company was a club to which one belonged. Considering the traditional lifetime employment system in which it was impossible to leave a company once employment had been entered, this is particularly ironic.
The reason for this digression is to make the point that Japanese companies, like Japanese individuals, also have their seals. These are larger (up to 3cm square), and complex, with the company name in full engraved in stylised script. While we still use the expression "signed and sealed" in the West, this takes on a new meaning in Japan.
The official (pre-printed) seal at right of NTT (Nippon Telegraph and Telephone Company) as it appears on my itemised phone bill in order to make it a valid receipt for the tax man
Not only large official documents, such as Articles of Incorporation, require the company seal, but such day-to-day items as quotations, receipts, and invoices must all pass under the eye of the person (usually the senior secretary) who keeps the company seal in a locked box.

Where does this lead?

Actually, it leads to chaos. Since it's possible to buy an "off-the-shelf" seal, with, say, the name Suzuki on it, it is possible to walk into anywhere where Mr. Suzuki is known and claim that Mr. Suzuki authorised you to use his seal (i.e. you are effectively signing in Mr. Suzuki's name). You can even pretend to be Mr. Suzuki and place orders, etc. in his name, with or without his knowledge. As a foreigner with a non-stock name, I am, thankfully, protected against this kind of fraud.

It's possible to lend your seal to a subordinate and authorise the subordinate to authenticate documents on your behalf. Since the seal has the force of a signature, you are bound by whatever piece of paper the subordinate chooses to embellish with your seal. Incidentally, credit cards are signed, but the signature is never checked.

In the not-for-profit organisation where I worked part-time helping with the English-language correspondence, the signatures of the elected officers are reproduced in the form of rubber stamps and used to "sign" official letters written by the secretariat to Ambassadors, other elected officers in other countries, official letters of invitation for the purpose of obtaining visas for overseas guests and so on and so forth. No-one seems to think it is odd that these official letters are not personally signed by the officers.

Whoever has the company seal likewise has the full force and authority of the company while they hold the seal. The person officially speaking for the company therefore can be anyone who holds the keys to the seal box.

Passing the buck (seal)

There is a general reluctance to take individual responsibility for actions in Japan, as we can see in the recent wave of financial disasters, where accountability has gone out of the window in Japan's largest banks and brokerage houses. The seal system helps to preserve this lack of responsibility (or maybe it helped to create it -- this is a Whorfian argument that I don't intend to get into). Since power is a temporary thing, wielded by whoever has the seal at the time, it is easy for a manager to dismiss actions as having been taken by subordinates, without his knowledge, and he therefore cannot be blamed for this. At worst, he will be "demoted" from President of the company to Chairman of the Board.

This, coupled with the general Japanese insistence on a third-party guarantor who will make sure that an individual's or company's debts and actions are satisfactorily covered (for instance when renting accommodation or making any kind of formal agreement) means that most baby-boomer Japanese are totally unprepared to take any positive actions or make any decisions of any importance, since it's always "somebody else's problem".

It seems that until Japanese people come to terms with the concepts of personal responsibility and initiative, as expressed, for example, by signing one's name on behalf of an organisation, and being allowed to rent property on the strength of their own say-so, the Japanese economic mess will continue, while the bureaucrats and business community refuse to take any action which may lead to fingers being pointed in their direction.