A Hanko (はんこ or 判子) is a personal seal used in Japanese society as a substitute for handwritten signatures. Typically made from materials such as hardwood, jade, or ox horn, these seals are compact and portable, featuring the owner's name (usually in Kanji) engraved on the surface. Their primary function is to verify identity and confirm consent, making them widely used in both daily life and business activities. Depending on their purpose, they are generally categorized into three types: "実印" (registered seal), "銀行印" (bank seal), and "認印" (everyday seal).

The use of hanko remains deeply embedded in Japanese society. From routine tasks such as signing for parcels and opening bank accounts to more formal procedures like signing contracts or registering with government agencies, imprinting one's personal seal is often required. The history of hanko dates back to China's Han Dynasty. After being introduced to Japan, it was initially adopted by the nobility as a symbol of status and authority. It wasn't until the Meiji period that hanko became commonplace among the general public, evolving into an essential everyday item.

Although the Japanese government has been promoting digitalization and aims to phase out mandatory hanko use in certain administrative processes, the seal remains a culturally significant object, representing tradition and trust. For visitors to Japan or foreigners planning to settle there, understanding—and even obtaining—a hanko offers valuable insight into Japanese social customs.