Brunei–Malaysia border which are defined by agreements, from west to east, are as follows: Brunei and Malaysia in an Exchange of Letters on 16 March 2009, agreed to affirm the five agreements. The two countries also agreed to use the watershed principle to determine the remaining undelimited portions of the border. Brunei's maritime boundary with Malaysia until the 100 fathom isobath was inherited from the Sarawak (Definition of Boundaries) Order in Council 1958 No 1518 and the North Borneo (Definition of Boundaries) Order in Council 1958 No 1517, both of which defined the boundary between Brunei on the one hand, and Sarawak
Brunei and Malaysia Brunei and Malaysia Brunei and Malaysia: " Why Sultan Omar Ali Saifuddin Refused to Join the Federation " is a 2013 book written by Isa Bin Ibrahim, a prominent member of the delegation of Sultan Omar Ali Saifuddin of Brunei with Neil Lawson QC, a London lawyer acting as the constitutional adviser on the formation of Malaysia. The book offers an inside perspective on Brunei's determination to retain its territory as an oil-rich self-governing state, contrasted with the British desire that Brunei should become part of the new federation to help counter the regional influence of China. Tunku Abdul Rahman