Emperor Meiji began a modernisation programme of Japan’s armed forces from 1868 onwards by partnering with Britain and Germany. Naval officers were sent to Britain and army officers to Germany. These officers imbibed the military culture of their hosts. Equipment was bought from both to complement their professional training. Japan’s armed forces were modern, well equipped and led by an elite military class. Russia under-estimated Japan’s military capacities because of institutional racism. The Japanese demonstrated their expertise in two decisive battles fought in 1905: Mukden and Tsushima. Russia was crushed in both.

The Emperor Meiji: Notice his western haircut and military uniform
The Treaty of Tianjin, 1860 (the Unequal Treaties), left China defenceless against quasi-colonialisation. Japan joined the imperial community after their triumph in Korea, 1894. This victory was a statement of intent in the future dismemberment of China, which led to conflict with Russian ambitions in the far east. Britain and Germany dismissed Russia’s pretensions,classifying them as second rate.The Japanese high command embraced this analysis, making them confident they’d win a war with Russia.
Russia signalled their imperial commitment by building the Trans-Siberian railway. The railway, Moscow to Vladivostok, threatened Japanese ambitions because it meant the military could move quickly from European Russia to the far east. The Russo-Japanese war began prior to the railway’s completion. The Japanese army crushed the Russians at Mukden and three months later in May 1905, the Russian fleet was annihilated. Japan’s comprehensive victories should have been ‘rewarded’ with territory but wasn’t. This outcome happened at the American Treaty of Portsmouth, September 1905.
Russia’s defeat was misinterpreted as weakness rather than Japanese strength. This is important as the Germans developed battle plans for a two-front war with France and Russia. The Schlieffen Plan, 1905-6, was predicated on a two-front war, including ‘knock-out’ victories. The plan depended on Russia’s fragility. It failed because resources diverted to the eastern front weakened the all-important western front with France. Four years of stalemate was compensated for by victory over Russia following the Bolshevik Revolution. Germany ultimately lost because the Bismarckian doctrine that two-front wars are unwinnable was correct. Great Power politicians ignored Japan’s contribution in the victory over Germany at the Versailles treaty.
Woodrow Wilson’s racism was unconcealed at the Treaty of Versailles, 1919.
….Japanese delegates felt humiliated by their peers at Versailles. At one important juncture, Japan proposed a “racial equality clause” to guarantee equal treatment of foreign nationals regardless of race. When put to a vote, the clause gained majority support among the assembled diplomats. But sitting in the chair, U.S. President Woodrow Wilson ruled that the equality clause should not be included in the final agreement because unanimity had not been reached—the only instance during the entire Versailles conference that undivided consent was insisted upon.*
The USA humiliated the Japanese in the 1930s by repudiating their ‘right’ to an empire in China. Japan’s sphere of influence was eastern China and in 1931 “Japan announced that it had annexed Manchuria and renamed it “Manchukuo.”** This was an imperialist carve-up of a defenceless country. The ensuing full-scale war, and especially the Rape on Nanking, 1937 alienated world opinion, attracting increasingly severe American sanctions.
In July 1941, the U.S. completely embargoed resources to Japan and froze all Japanese assets in American entities. American policies forced Japan to the wall.***
These sanctions meant Japan had to capitulate or fight. They fought. Pearl Harbour was the result.
The Russo-Japanese war is important because it created an unrecognised Great Power. The consequence was repeated Japanese humiliation by the other Great Powers. Racism blinded Germany to Japanese strength and an over-estimation of Russian weakness. This contributed to the causes of the First World War. The USA failed to recognise their racist diplomacy was a provocation, which led to the Pacific War, 1941-5. They too failed to understand that they were facing a resilient opponent. The Russo-Japanese war is crucial in understanding the 20th century because the Great Powers failed to recognise imperialism in an Asian context.
Notes
** https://www.thoughtco.com/the-us-and-japan-before-world-war-ii-3310162
*** loc.cit
Sources
For the treaty of Tianjin see https://www.historytoday.com/archive/months-past/treaties-tianjin
For the treaty of Portsmouth see https://history.state.gov/milestones/1899-1913/portsmouth-treaty
For the Rape of Nanking see https://www.history.com/this-day-in-history/the-rape-of-nanking For the historical context of military and cultural abuses in China see http://archive.ifla.org/IV/ifla62/62-davd.htm The Japanese regarded the western Great Powers as complete hypocrites for their condemnation.
For Japanese involvement in the First World war see https://en.wikipedia.org/wiki/Japan_during_World_War_I