Safety Headquarters Navigational Warnings, Maritime Safety Offices Navigational Warnings, as well as Notices to Mariners. Furthermore, it provides navigational warnings through the World-Wide Navigational Warning System (NAVAREA XI Navigational Warnings and NAVTEX Navigational Warnings).
a. Notices to Mariners
(i) Notices to Mariners are issued once a week in the form of booklet containing information to keep nautical charts and publications up-to-date and information regarding matters that are necessary for maritime traffic safety, such as changes in aids to navigation, construction and work at sea, and firing or bombing exercises by the Japanese Self-Defense Forces or the U.S. Forces, etc.
(ii) Regional Notices to Mariners are issued once a week in the form of booklet containing information necessary for maritime traffic safety that is specific to the sea area a Regional Maritime Safety Headquarters is in charge of and its surrounding sea areas.
b. Navigational Warnings
(i) Japan Navigational Warnings provide information, such as information regarding drifting objects, which must be reported urgently for safe navigation, in Japanese using radiotelegraph transmitted at fixed intervals (at any time in case of particular urgency, such as submarine volcanic eruptions), to Japanese vessels at sea from the western part of the North Pacific Ocean to the vicinity of Persian Gulf.
(ii) Regional Maritime Safety Headquarters Navigational Warnings and Maritime Safety Offices Navigational Warnings provide vessels navigating the coastal waters of Japan with information about parts to which the Port Regulations Law applies and its vicinities which must be reported urgently for safe navigation at any time by radio-telephone.
(iii) Maritime Traffic Information provide ships passing through sea areas with heavy ship traffic with information that must be reported urgently for safe navigation, using radio-telephones, electric signboards, etc., at fixed intervals or at all any time.
(iv) NAVAREA Navigational Warnings provide information related to the sea area through which a ocean-going vessel is navigating, based on the World-Wide Navigational Warning System.
Of the 16 Areas into which the world's oceans (excluding the Arctic Ocean and Antarctic Ocean) are divided, Japan is in charge of Area XI (western part of the North Pacific Ocean and the Southeast Asian sea area). It provides
