Philippine Civil Code, Art. 972

Representation lets a person step into the place and degree of a nearer relative who cannot or does not inherit. It operates without limit in the direct descending line — grandchildren, great-grandchildren and so on — and never in the ascending line, so a grandparent cannot represent a parent. In the collateral line it is confined to the children of the decedent's brothers and sisters, whether of the full or half blood, and goes no further: a grandnephew does not represent. Article 973 adds that the representative must himself be capable of succeeding the decedent, and Article 975 shows the rule at work — nephews and nieces inherit by representation when they concur with uncles or aunts, but in equal portions in their own right when they survive alone.