In the Philippine legal system, when a person dies without a valid will, or if the will is void or has subsequently lost its validity, intestate succession takes place. Under the Civil Code of the Philippines, the law essentially "writes a will" for the deceased, based on the presumed affection of the decedent for those closest to them.

Succession is governed by the principle that "proximity of degree excludes the more remote," subject to the right of representation.

1. The Order of Intestate Succession

The law establishes a strict hierarchy of who inherits from the estate. The presence of certain heirs excludes others from the succession. The general order is as follows:

Legitimate Children and their Descendants
Legitimate Parents and Ascendants (only in the absence of #1)
Illegitimate Children and their Descendants
Surviving Spouse
Brothers and Sisters, Nephews and Nieces
Other Collateral Relatives (up to the fifth degree of consanguinity)
The State

2. Rights of the Surviving Spouse

The surviving spouse is a compulsory heir. In intestate succession, the spouse’s share varies depending on who else survives the decedent. Unlike other heirs, the spouse is never excluded by the presence of children or parents; instead, they concur with them.

Key Scenarios for the Surviving Spouse:

With Legitimate Children: The surviving spouse has the same share as each of the legitimate children. If there is only one legitimate child, the spouse gets 1/2 and the child gets 1/2.
With Legitimate Parents: The spouse is entitled to 1/2 of the estate, and the parents are entitled to the other 1/2.
With Illegitimate Children: The spouse is entitled to 1/2, and the illegitimate children divide the remaining 1/2.
Alone: If there are no descendants, ascendants, or siblings, the surviving spouse inherits the entire estate.
With Brothers, Sisters, Nephews, or Nieces: The spouse is entitled to 1/2, and the remaining 1/2 goes to the siblings or their children.

3. Distribution of Shares (Table of Intestacy)

The following table summarizes the distribution of the estate based on the combination of surviving heirs:

Surviving Heirs	Share of Spouse	Share of Children/Parents
Spouse + Legitimate Children (LC)	Share of 1 LC	Estate divided equally (Spouse counts as 1 LC)
Spouse + 1 Legitimate Child	1/2	1/2
Spouse + Legitimate Parents (LP)	1/2	1/2
Spouse + Illegitimate Children (IC)	1/2	1/2 (Divided among IC)
LC + IC	(Not applicable)	LC get 1 share each; IC get 1/2 share of 1 LC
Spouse + LC + IC	Share of 1 LC	LC (1 share each); IC (1/2 share of 1 LC)
Spouse + LP + IC	1/4	LP (1/2); IC (1/4)
Spouse Alone	1/12 (Total)	None

4. The Right of Representation

The Right of Representation is a legal fiction wherein the representative is raised to the place and the degree of the person represented, acquiring the rights which the latter would have had if they were living or could have inherited.

When it applies: In cases of pre-decease (dying before the decedent), incapacity, or disinheriting.
Note: Representation does not apply in cases of repudiation (renouncing the inheritance). If an heir repudiates their share, their own heirs cannot represent them.
Lineage: In the direct descending line, representation is ad infinitum. In the collateral line, it only takes place in favor of children of brothers or sisters (nephews and nieces).

5. Important Legal Doctrines

The "Iron Curtain" Rule (Article 992)

A significant provision in Philippine succession is Article 992, which prohibits an illegitimate child from inheriting ab intestato (by intestacy) from the legitimate children and relatives of their father or mother. Conversely, the legitimate relatives cannot inherit from the illegitimate child.

Note: Recent jurisprudence (Aquino v. Aquino, 2021) has clarified that this "curtain" may be breached in specific circumstances regarding grandchildren, emphasizing the best interests of the child, though the statutory rule remains a primary hurdle in collateral succession.

The Rule of Proximity

The relative nearest in degree excludes the more distant ones. Degrees are counted by generations. For example, a child (1st degree) excludes a grandchild (2nd degree) unless the right of representation is triggered.

Exclusion of the State

If there are no relatives up to the fifth degree and no surviving spouse, the estate is escheated in favor of the State. The property will be assigned for the benefit of public schools and public charitable institutions in the locality where the decedent resided or where the property is situated.

6. Summary of Rights

Legitimate Children: Always entitled to at least half of the estate (the legitime) and usually the bulk of the remainder in intestacy.
Illegitimate Children: Entitled to a share that is exactly half of the share of a legitimate child, provided the total does not exceed the free portion of the estate.
Surviving Spouse: Inherits as a primary compulsory heir, with the share varying based on the "concurrence" of other heirs.
Collaterals: Only inherit if there are no descendants, ascendants, or surviving spouse.