How can I obtain a design right? Are products for which design rights have been obtained overseas protected in Japan?

In order to obtain a design right, documentation in legally prescribed format is required.

1. In order to obtain a design right, you need to prepare an application and drawings in Japanese and file them with the Commissioner of the Patent Office. The drawings are the most important factor in determining a range of design rights, so they must be prepared in accordance with the prescribed methods. Application fees must be paid in special Patent Revenue stamps.
A person who does not have an address in Japan (business office in the case of a juristic person) can only apply through a Japanese patent attorney who resides in Japan (Japanese lawyers can offer services what patent attorneys do).
Before you file a design application, you should make a preliminary design search at the Industrial Property Digital Library (IPDL) of the Patent Office, in order to avoid filing an application unnecessarily. A design application which includes the same or similar design already known before the application is filed will be refused. Design applications are examined without request for an examination. The required contents for an examination are as follows:

The design should have a shape, pattern, color or a combination of these in an article (including part of an article) and should be a good visual representation;
The design should be industrially utilized;
The design should be new;
The design should not be easily created;

2. Your design cannot be protected in Japan by virtue of having obtained a design right in another country. Therefore, if you want to import a product with a design right into Japan, it is necessary to file a design application in Japan in advance to secure the design right. However, any national of member nations under the Paris Convention may claim conventional priority by filing the same design application, as one filed in any country under the convention, in Japan within six months from the filing date in the first country where it was filed.

3. Customs confirms whether or not cargo to be imported infringes on intellectual property rights such as design rights. If the imported cargo appears to be infringing, procedures in order to approve the presence of infringement of the relevant cargo are taken. At that time, an opportunity to state opinions is given to both the rightful person and the importer by presenting evidence. Furthermore, special handing is given by customs for cargo for which the design right holder filed a "submission of import prohibition information".