The Ocean Drilling in the 21st Century (OD21) project, being promoted by the Japan Marine Science and Technology Center (JAMSTEC), is intended to elucidate the mechanisms of global change, including climate changes and earthquakes, search for signs of life in the earth's crust, and inquire into the state of deposits and origin of methane hydrate, in an effort to create and facilitate understanding of new geosciences and biosciences. The Deep Sea Drilling Vessel"CHIKYU" (riser drilling type) will be built and operated to serve the objectives of the project.

An earlier Deep Sea Drilling Project, launched back in 1968, resulted in several significant achievements, including the verification of plate tectonics and confirmation of the mild and warm global environment of some 100 million years ago. This project has been succeeded by the international Ocean Drilling Program (ODP). The ODP, which now uses a U.S. deep sea drilling vessel (non-riser type) and benefits from the participation of 22 countries, is scheduled to end in 2003.