The spouse of a decedent will always be an heir (Civil Code Art. 890).

 With regard to the priority of heirs by blood

 1  Child

 2  Lineal Ascendants

 3  Siblings

 (Civil Code Art. 887(1), 889(1))

Adopted cildren are regarded as children, and are heirs.

Minors, unborn children, and absentees are heirs.

If a decedent‘s child has died before the commencement of inheritance, the child of the decedent’s child shall be an heir as an heir per stirpes; provided that this shall not apply if the child is not a lineal descendant ofthe decedent.

If the child of the decedent’s child has died before the commencement of inheritance, the child of the child of the decedent's child shall be an heir as an heir per stirpes.

 (Civil Code Art.887(2),(3))

 This means, the decedent’s grandchildren will be the heirs if the decedent’s child had passed away before the decedent passed away.

 If the decedent’s grandchildren passed away before the decedent passed away, the decedent’s great-grandchildren will be heirs.

 ×the decedent’s child 　             ○the decedent’s grandchildren

 ×the decedent’s grandchildren ○the decedent’s greatgrandchildren

If a decedent's sibling has died before the commencement of inheritance, the child of the decedent's sibling shall be an heir as an heir per stirpes; provided that this shall not apply if the child is not a lineal descendant of the decedent.(Civil Code Art.889(2))

 This means that the decedent’s niece or nephew will be an heir if the decedent’s sibling had passed away before the decedent passed away .

 ×the decedent’s siblings   ○the decedent’s niece or nephew