I began to play against my relations and friends, but I soon found that I could beat them without any difficulty.

relations 是 relation 的复数形式，relation 的基本意思是"关系"，在这里特指"有血缘或婚姻关系的亲属"。 relations and friends 这个短语指的是"亲戚和朋友"，其中 relations 强调血缘或法律关系，friends 则指非亲属关系的朋友。