The Penal Code of Japan contains a chapter on the crime of forgery of seals in Chapter 19 of the Japanese law. It is a crime to counterfeit any seal, official or private. Therefore, it is prohibited by law to create a seal with the same impression. The concept of seal in the Penal Code includes not only the impression of the seal, but also the seal itself.
In other words, forging a seal impression on paper is also a crime. If the seal or other seal is chipped, it is recommended that a new hanko be made with a different seal impression. If the hanko you have been using is a registered hanko, you should promptly complete the registration change procedure at the same time.