Many years ago, when I first became an eikaiwa instructor at NOVA, I received a wooden stamp with my name carved into it in Japanese. I thought it was so cool. I thought of myself like an old English king sealing letters with a stamp in hot wax on papyrus. I was told this stamp would be necessary for any major paperwork in Japan, e.g., registration at a local city hall or ward office, opening a bank account, and applying for jobs. There are two kinds of stamps.
This is the important one you hide in a cabinet inside a case. It’s used for official purposes such as confirming your identity with banks, applying for major loans, and marriage documentation. You can only have one.
This is the one you leave at work, in your bag, or by the door to use in place of a signature for everyday things. You can have several different ones, as many as you like. It’s not a big deal if you lose one, either.
While most countries use a signature, Japan strongly believes in registered stamps. Japan even forced Korea to adopt this system during the Japanese occupation. South Korea officially dropped this system, believing it to be inefficient and easily susceptible to fraud.