OSEI v. SIRIBOUR II Chieftaincy—Cause or matter affecting chieftaincy—Meaning of—Mere claim to membership of royal family—Such claim cognisable by ordinary courts and not triable by chieftaincy tribunal—Such claim not implying a claim to be elected or installed chief at some future occasion—Circumstances for determining existence of cause or matter affecting chieftaincy—Existence of vacancy vital—Whether mere claim to membership of royal family constituting chieftaincy matter depending on peculiar facts of each case—  Chieftaincy Act, 1971 (Act 370), s. 66 (a) and (d).