"Serial number" refers to the unique number used in specific works in Japan, such as AV, TV programs, comics, etc. These numbers are usually similar to the names of works on streaming media websites and DVDs, but they all have unique serial numbers. If you know the serial number of a work, you can easily find it online.

The adult video industry in Japan is world-famous, so the topic of "designation" is still very popular in Japan. On the Internet, there are many websites that provide the serial number library of AV works, which is convenient for users to find specific works. These websites even provide search functions, including thumbnails, summaries and ratings, to help users better choose the movies they want.

Although the word "serial number" is commonly used in Japan to identify adult works, it is also widely used in other industries. For example, some specific chapters or levels in comics and games will also have corresponding numbers. Other companies use serial numbers to identify their products to help customers better distinguish different kinds of products. Generally speaking, serial number is a very common term in Japan. It is not only an important tool for users to find specific works, but also plays an important role in product identification and classification.