3 'twenty-year' rules in the Civil Code

All provisions below are taken from the Civil Code of the Philippines. The Civil Code of the Philippines is the product of the codification of private law in the Philippines. It is the general law that governs family and property relations in the Philippines. It was enacted in 1950, and remains in force to date with some significant amendments. SOURCE: Civil Code of the Philippines. From Wikipedia, the free encyclopedia. https://en.wikipedia.org/wiki/Civil_Code_of_the_Philippines

The first provision below is about co-ownership. The last two are under the law on succession (wills and succession).

Article 494. No co-owner shall be obliged to remain in the co-ownership. Each co-owner may demand at any time the partition of the thing owned in common, insofar as his share is concerned.

Nevertheless, an agreement to keep the thing undivided for a certain period of time, not exceeding ten years, shall be valid. This term may be extended by a new agreement.

A donor or testator may prohibit partition for a period which shall not exceed twenty years.

Neither shall there be any partition when it is prohibited by law.

No prescription shall run in favor of a co-owner or co-heir against his co-owners or co-heirs so long as he expressly or impliedly recognizes the co-ownership.
Article 870. The dispositions of the testator declaring all or part of the estate inalienable for more than twenty years are void.

Article 1083. Every co-heir has a right to demand the division of the estate unless the testator should have expressly forbidden its partition, in which case the period of indivision shall not exceed twenty years as provided in article 494. This power of the testator to prohibit division applies to the legitime.

Even though forbidden by the testator, the co-ownership terminates when any of the causes for which partnership is dissolved takes place, or when the court finds for compelling reasons that division should be ordered, upon petition of one of the co-heirs.