Which naval treaty actually limited destroyer size

Did the treaty system cap individual destroyer displacement, or only a navy's total destroyer tonnage?

Washington supplied the 10,000-ton capital-ship threshold, while the London treaties introduced the destroyer-specific limits and category tonnage rules.

The Washington Naval Treaty defined ships above 10,000 tons as capital ships and standardized what its ton meant, but it did not provide the destroyer rules in question. Destroyer-specific limits appeared in the London treaty system, including a 1,800-ton figure and wider category allowances. The distinction matters because later destroyer design pressure cannot be attributed to every interwar treaty at once. This exchange shows how the legal framework changed between treaty rounds and why precise treaty attribution matters.