Two K3s would reshape the Washington treaty

What happens if two K3s enter service before the Washington Naval Treaty?

Britain keeps them, and the treaty either changes radically to accommodate 18-inch ships or fails to take its historical form.

Britain would be very unlikely to scrap brand-new K3s merely to reproduce the historical treaty. Hood had already shown that London would threaten to walk away rather than sacrifice a new capital ship. Possible alternatives include folding the K3s into British tonnage, allowing comparable American and Japanese construction, or creating a 5:5:3 allocation specifically for 18-inch-gunned ships. Any choice produces a fundamentally different treaty and stronger responses than the historical South Dakota and Number 13 programs, with Japan facing the greatest financial strain.