When Philippine law directs the application of a foreign national's law to matters of succession, the term "national law" is understood to encompass the entirety of that foreign law, including its conflict-of-laws rules. If the foreign law contains a conflict-of-laws rule that refers the matter back to the law of the decedent's domicile, the Philippine court shall accept this referral (renvoi) and apply its own internal law on succession.

Edward E. Christensen, a citizen of the State of California, lived for most of his life in the Philippines, where he died. He left a will that provided a legacy of P3,600 to Helen Christensen Garcia, who had been judicially declared his acknowledged natural child in a separate proceeding, while leaving the bulk of his substantial estate to his other daughter, Maria Lucy Christensen. This disposition was valid under the internal law of California, which grants testators complete freedom of disposition. However, it contravened Philippine law, which designates acknowledged natural children as forced heirs entitled to a specific portion of the estate known as the legitime. The conflict arose as to which law should govern the intrinsic validity of the will's provisions.

• Edward E. Christensen, a citizen of the United States and the State of California, died in Manila, Philippines, on April 30, 1953, with the Philippines being his established domicile.
• He executed a will in Manila on March 5, 1951, bequeathing P3,600 to Helen Christensen Garcia and leaving the residue of his estate to his other daughter, Maria Lucy Christensen Daney.
• The will explicitly stated that Helen, despite being baptized with his surname, was not related to him in any way.
• However, in a prior case (G.R. Nos. L-11483-84), the Supreme Court had already declared Helen Christensen Garcia to be the acknowledged natural child of the deceased.
• The executor of the estate, Adolfo Aznar, submitted a project of partition based on the will, which Helen opposed on the ground that it deprived her of her legitime as a forced heir under Philippine law.
• It was undisputed that Christensen was a citizen of California but was domiciled in the Philippines at the time of his death.

• The executor and heir-appellees argued that pursuant to Article 16 of the Philippine Civil Code, the successional rights should be governed by the national law of the deceased, which is the law of California.
• They contended that under California's internal law, a testator has the absolute right to dispose of his property by will in any manner he desires, without being constrained by the concept of legitime for forced heirs.
• They asserted that the "national law" mentioned in Article 16 of the Civil Code refers only to the internal substantive law of California, not its conflict-of-laws rules.

• The oppositor-appellant, Helen Christensen Garcia, argued that the distribution of the estate should be governed by the laws of the Philippines, where the decedent was domiciled.
• She contended that the "national law" under Article 16 of the Civil Code refers to the entire law of California, including its conflict-of-laws rules.
• She invoked Section 946 of the California Civil Code, a conflict-of-laws rule stating that personal property is governed by the law of the owner's domicile.
• Applying the renvoi doctrine, she argued that since California law refers the matter back to the law of the domicile (Philippines), Philippine law on succession and legitimes must be applied.

• Procedural Issues:
  • N/A
• Substantive Issues:
  • Whether the intrinsic validity of the testamentary provisions of the deceased, a citizen of California domiciled in the Philippines, should be governed by the internal law of California or the law of the Philippines.

• Procedural:
  • N/A
• Substantive:
  • The Supreme Court reversed the decision of the lower court and ruled that the laws of the Philippines should govern the succession. The Court reasoned that Article 16 of the Philippine Civil Code, which mandates the application of the decedent's national law, requires an examination of the entire foreign law, including its conflict-of-laws rules. The Court found that Section 946 of the California Civil Code directs that matters of succession to personal property are governed by the law of the decedent's domicile. Since Christensen was domiciled in the Philippines, California's conflict-of-laws rule "refers back" the case to Philippine law. To prevent an endless cycle of referrals, the Philippine court must accept the reference and apply its own internal laws. Therefore, the provisions of the Philippine Civil Code concerning legitimes of forced heirs are applicable, and the partition of the estate must be made in accordance with Philippine law.

• Lex Nationalii — This principle, found in Article 16 of the Philippine Civil Code, states that intestate and testamentary successions shall be regulated by the national law of the person whose succession is under consideration. The Court applied this by first looking to the law of California, but interpreted "national law" to mean the whole law of California, including its choice-of-law rules.
• Renvoi Doctrine — This is the primary doctrine applied. It is a process where a forum court, in applying the law of a foreign state as directed by its own conflict-of-laws rule, discovers that the foreign state's conflict-of-laws rule would send the case back to the forum's law. In this case, Philippine law pointed to California law (lex nationalii), and California law (via Section 946) pointed back to Philippine law (lex domicilii). The Court accepted this "remission" or "reference back" and applied its own domestic law to resolve the issue.
• Domiciliary Theory — The Court recognized that California's conflict-of-laws rule for personal property succession (Section 946) follows this theory, which posits that the law of the person's domicile governs. This was the basis for California law referring the matter back to the Philippines.

• "The conflict of law rule in California, Article 946, Civil Code, precisely refers back the case, when a decedent is not domiciled in California, to the law of his domicile, the Philippines in the case at bar. The court of the domicile can not and should not refer the case back to California; such action would leave the issue incapable of determination because the case will then be like a football, tossed back and forth between the two states, between the country of which the decedent was a citizen and the country of his domicile."

• In re Kaufman — Cited by the appellees to argue that California law grants absolute testamentary freedom. The Supreme Court distinguished this by explaining that this case represents California's internal law applicable to its residents, not its conflict-of-laws rule for citizens domiciled elsewhere.
• In Re Estate of Johnson; Riera vs. Palmaroli; Miciano vs. Brimo — These were Philippine cases cited by the appellees. The Supreme Court found them inapplicable because, in those cases, it was not established that the foreign national law in question contained a conflict-of-laws rule that would refer the succession issue back to the law of the domicile, unlike the specific provision in California's Civil Code.

• Article 16, Philippine Civil Code — This is the controlling conflict-of-laws rule in the Philippines for succession. It provides that successional rights are governed by the national law of the decedent. The Court's interpretation of what constitutes "national law" was the central point of the case.
• Articles 887(4) and 894, Philippine Civil Code — These articles establish acknowledged natural children as compulsory heirs and define the extent of their legitime under Philippine law. They were the basis for Helen Christensen Garcia's claim once the Court determined Philippine law was applicable.
• Section 946, California Civil Code — This is the specific conflict-of-laws rule from California which states: "If there is no law to the contrary, in the place where personal property is situated, it is deemed to follow the person of its owner, and is governed by the law of his domicile." This provision triggered the application of the renvoi doctrine.