This edition of MAL 1 is based upon the "Chart Specifications of the International Hydrographic Organisation (IHO), which came into force at the Xllth International Hydrographic Conference 1982 in Monaco. The system of numbering in this edition uses letters prefixed "M" to indicate the initial for Malaysia. MAL 1 contains the complete symbols and abbreviations used on international as well as national charts of the National Hydrographic Centre, Royal Malaysian Navy (NHC)