Nippon Kaiji Kyokai, known as ClassNK or NK, is a ship classification society. The Society is actively engaged in a growing range of ship related activities and services aimed at contributing to promoting the protection of human life and property at sea as well as protection of the marine environment.

ClassNK has earned an outstanding reputation for its long-standing dedication to safeguarding life and property at sea and preventing marine pollution through the establishment of universally recognized standards for the design, construction and maintenance of ships and other marine structures.

The principal work of the Society’s expert technical staff is to undertake surveys to ensure that the rules which it has developed are applied to new buildings and existing ships to ensure their safety. The rules cover not only hull structures, but also propulsion systems, electronic systems, safety equipment, cargo handling gear, and various other areas. ClassNK’s surveyors work in shipbuilding and repair yards and at ports across the world, wherever they may be called upon to examine the condition of a ship.

The Nippon Head Office is located in Tokyo and in Chiba, Japan, and there are branch offices at the major Japanese ports and overseas offices throughout the world. As of December 2010, the Society had 7,347 ships over 180 million g.t. under class. This figure represents approximately 20 percent of the world merchant fleet currently under class.

In addition to its classification activities, ClassNK conducts surveys on behalf of third parties including State administrations, offers technical services for marine and non-marine construction projects, accommodates requests for appraisals and engineering consultation, conducts research and development in various ship-related fields; provides quality-assurance certification of suppliers based on ISO 9000 and 14001 series criteria, and verifies the safety management systems of ship-management companies and ships, in accordance with the International Safety Management (ISM) Code and International Ship and Port Facility Security (ISPS) Code.