The Nippon Decimal Classification (NDC, also called the Nippon Decimal System) is a system of library classification developed for mainly Japanese-language books maintained and revised by the Japan Library Association since 1948. Originally developed in 1929 by Kiyoshi Mori, the 10th and latest edition of this system was published in 2014. The decimal notation system is similar to the Dewey Decimal System, and the order of main classes is inspired from the Cutter Expansive Classification. The system is based upon using a three digit number to classify subjects, where more digits can be added if necessary and a decimal point is used to separate the third and fourth digit. The first division level is called a class, the second level is called a division, and the third level is called a section. Each '1-9' digit is used to represent a specific category, with the digit '0' being used to represent general works.
The system is made up of ten categories:
The General category contains books that contain general information, rather than information about specific topics. The sub-categories of the General category are:
The Philosophy category contains books that contain information regarding philosophy, religion, and psychology. The sub-categories of the Philosophy category are:
The History category contains books that contain information regarding local and foreign history. The sub-categories of the History category are:
The Social Sciences category contains books that contain information regarding modern day society, such as government systems and cultural traditions. The sub-categories of the Social Sciences category are:
The Natural Sciences category contains books that contain information regarding the natural world, such as plants, animals, and natural laws, such as math and physics. The sub-categories of the Natural Sciences category are:
The Technology & Engineering category contains books that contain information regarding man-made scientific achievements. The sub-categories of the Technology & Engineering category are:
The Industry and Commerce category contains books that contain information regarding business, products, transportation systems, and money. The sub-categories of the Industry and Commerce category are:
The Arts category contains books that contain information regarding various art forms, such as paintings, writing, and music. The sub-categories of the Arts category are:
The Language category contains books that contain information regarding various languages spoken around the world. The sub-categories of the Language category are:
The Literature category contains books with fictional content, such as romance novels and adventure stories. The sub-categories of the Literature category are: