Answer
To recover ownership through an accion reivindicatoria, the plaintiff must prove two things: the identity of the property claimed and the strength of his own title (Civil Code Article 434). The plaintiff must rely on the strength of his own evidence of ownership and not on the weakness of the defendant's claim; a failure to fix the identity of the land or to establish a superior title defeats the action.
Ownership may be shown by a Torrens certificate of title, a title recognized under law, or acquisitive prescription over unregistered land (ten years in good faith with just title, or thirty years regardless of title). Registered land under the Torrens system is generally imprescriptible — it cannot be acquired by another through adverse possession (Section 47, Presidential Decree No. 1529).