Editing Battle of Tsushima (section)

===Dreadnought arms race===
{{Main|Dreadnought|Anglo-German naval arms race}}
Prior to the Russo-Japanese War, countries constructed their battleships with mixed batteries of mainly 6-inch (152&nbsp;mm), 8-inch (203&nbsp;mm), 10-inch (254&nbsp;mm) and 12-inch (305&nbsp;mm) guns, with the intent that these battleships fight on the battle line in a close-quarter, decisive fleet action. The Battle of Tsushima conclusively demonstrated that faster battleships and big guns{{sfn|Massie|1991|pages=470–480}} with longer ranges were superior to batteries of mixed-size guns.{{sfn|Semenoff|1907|pages=125, 135}}

[[File:Colorized Satsuma.jpg|thumb|left|[[Japanese battleship Satsuma|Japanese battleship ''Satsuma'']], laid down on 15 May 1905, earlier than [[HMS Dreadnought (1906)|HMS ''Dreadnought'']], was designed with 12 x 12" 40 Cal. guns.<br>(She ended up with 4 x 12" 45 Cal. Armstrong plus 12 x 10" 45 Cal. Vickers guns and became the largest battleship in the world at launch in 1906.)]]
Britain's [[First Sea Lord]], [[Admiral Jackie Fisher]], reasoned that the Japanese victory at Tsushima confirmed the importance of large guns and speed for modern battleships.{{sfn|Massie|1991|pages=471, 474, 480}}{{sfn|Busch|1969|page=215}} [[William Pakenham (Royal Navy officer)|Captain William Pakenham]] of the British Royal Navy, who had been present aboard the Japanese battleship ''Asahi'' as an official observer during the Tsushima Battle, "famously remarked...the effect of the fire of every gun is so much less than that of the next larger size, that when 12in guns are firing, shots from 10in pass unnoticed...everything in this war has tended to emphasize the vast importance to a ship, at every stage of her career, of carrying some of the heaviest and furthest shooting guns that can be  got into her."{{sfn|Friedman|2008|page=68}} In October 1905 the British started the construction of {{HMS|Dreadnought|1906|6}}, which marked the beginning of a naval arms race between Britain and Germany in the years before 1914.{{sfn|Turner|1913|pp=129–147}}

The battle also accelerated the naval arms race on a geopolitical level; though the Anglo-German naval arms race had begun in 1897, the collapse of Russian naval power in 1905 allowed Britain to send the bulk of its naval forces to other regions, reassured by the naval superiority of its ally Japan in the Far East. In turn, the presence of a larger British fleet in Europe meant that the Germans must build a proportionally larger fleet to maintain the same relative power, in accordance with [[Alfred von Tirpitz|Tirpitz]]'s [[fleet in being]] principle. The Royal Navy, in turn, must increase its fleet size to maintain the relative power as set out by its [[two-power standard]]. This [[positive feedback]] meant that any external increase in the regional naval power of one side – in this case, the British – would precipitate not just a proportional increase in naval power from the opposing side, but rather a ''mutual'' multi-stage build-up in naval power on both sides, before settling to a higher equilibrium. Ultimately, the Germans passed three of its five [[German Naval Laws|Fleet Acts]] after Tsushima within a span of 6 years.{{sfn|Gardiner|Budzbon|1985|pages=134–135}}

Upon the breakout of [[World War I]], the British and Germans were both aware of the potentially devastating consequences of a naval defeat on the scale of Tsushima. Britain needed its battle fleet to protect its empire, and the trade routes vital to its war effort. Winston Churchill, then First Lord of the Admiralty, described British Admiral [[John Jellicoe]] as "the only man who on either side could lose the war in an afternoon."{{sfn|Churchill|1927|p=106}} German naval commanders, for their part, understood the importance Kaiser [[Wilhelm II]] attached to his navy and the diplomatic prestige it carried. As a result of caution, the British and German fleets met in only one major action in World War I, the indecisive [[Battle of Jutland]].<ref>{{Cite web|url=https://www.britannica.com/event/Battle-of-Jutland|title=Battle of Jutland &#124; History, Facts, & Outcome &#124; Britannica|website=www.britannica.com|date=24 May 2023 }}</ref>