How HMS Incomparable could rewrite the naval treaties

How would other navies and the treaty system react if Britain completed HMS Incomparable?

Japan and America would pursue larger replies, treaty limits could rise to 20-inch guns, and 16-inch weapons might become the new battleship baseline.

Japan would probably pursue something like the A-150, while the United States considered Tillman or Montana-scale answers. If existing Japanese yards could not take the enlarged design, Japan might adopt sectional construction inspired by French practice and join major hull sections after building them separately. Britain would not willingly discard Incomparable in treaty negotiations, so the permitted gun ceiling might rise to 20 inches. A practical British version would also gain armour and approach 50,000 tons rather than follow Fisher's light-protection concept unchanged. Once two British ships carried 20-inch guns, later 14-inch battleships would look inadequate and 16-inch weapons could become the minimum acceptable capital-ship battery.