Rule 44.1.Determining foreign law.

Rule 44.1 is short but consequential: a party who wants to raise an issue about the law of a foreign country must give reasonable written notice to the court and the other parties, so nobody is surprised by a foreign-law argument late in the case. In figuring out what that law provides, the court can consider any relevant material or source it finds useful, including testimony, whether or not a party submitted it and regardless of whether it would otherwise be admissible under the Arizona Rules of Evidence.

Just as important is what the rule does with the court's conclusion once reached: it is treated as a ruling on a question of law, not a factual finding. That distinction affects how the determination gets reviewed and used later in the case, aligning Arizona's approach with the modern view that foreign law is something for the court to determine, not something a jury weighs like disputed facts.