You can often hear that they won. It certainly looks like Russia was humiliated by the mere fact that great European power was not able to crush a relatively small Asian one. But when I read about it in wikipedia the language is evasive. It says that the war ended in Japanese victory but the peace agreement seems relatively tame for me. Treaty of Portsmouth article also says that Japanese people felt cheated by the treaty.
So what's the extent of Japanese victory?
Expanded from an earlier answer of mine
The Japanese government certainly did achieve a number of strategic goals in its war with Russia. It did manage to secure control of the Korean peninsula, which was one of the long-range goals for the genro (Meiji oligarchs) for several decades. The war eliminated Russia as a threat to Japan's interests in East Asia, China in particular. Defeat and revolution meant that the tsarist state could not continue its economic and political penetration into Manchuria. This left a vacuum that the Treaty of Portsmouth opened up to Japan via concessions and elements within the Japanese Army and Foreign Ministry built on these concessions to cleave out a puppet state within Manchuria. So the war did succeed on a number of metrics. But this declaration of victory might come as a surprise to observers of Japan's domestic scene in which Portsmouth ushered in a period of great civil unrest. One of the geographic epicenters for Japanese nationalism during the Russo-Japanese War was Hibiya Park in Tokyo- seen in this map. The park was adjacent to the imperial palace and was the site of numerous celebrations of Japanese victories during the war. It therefore was no surprise that Hibiya also became the focal point for popular discontent over the Portsmouth Treaty. The Hibiya Riots lasted over three days in September 1905 and were replicated in some of Japan's other larger cities. But the Hibiya protests were more complicated than just discontent over the peace terms and the rioting had multiple causes.
The most obvious bone of contention among the Hibiya rioters was that Japan received no indemnity from Portsmouth and the territorial concessions were rather small given the blood and treasure Japan had shed for its victory (although many Koreans would disagree that Japan received little from Portsmouth). A number in the Japanese nationalist press stoked up hopes that Japan would receive all of Sakhalin from Russia and that there would be wider gains in Manchuria. Japan's prior war with the Chinese also created a precedent of an indemnity placed on the defeated power to help pay for the costs of the war. The Sino-Japanese War also created a narrative of Western powers who cheated Japan out of her hard-fought gains. The Japanese had initially managed to wrest significant concessions from the Qing, but the Triple Intervention of the UK, France, and Russia forced Japan to scale back its demands on China. The American-brokered Portsmouth Treaty seemed to more than a few Japanese to be a retread of the Triple Intervention in which Western powers were holding Japan back.
Although the Japanese genro used mass mobilization to fight the war, they fought it much akin to a traditional cabinet war in which decision-makers focused on limited, but achievable goals. Japanese negotiators did push hard for an indemnity but soon recognized that such a concession was impossible. But the discrepancy between gains from wars and the investment needed to fight a truly modern war was such that it was bound to elicit public discontent. This presaged one of the dilemmas of modern warfare in an industrial age: how to end them. The resources mobilized to fight modern wars reinforced popular expectations of a final peace that would be worth such efforts. Peace treaties limiting gains in exchange for a realistic settlement seldom fit into the expansive visions of a triumphant nation. Ironically, using nationalism to fight these wars proved to be something akin to the fable of the sorcerer's apprentice in which nationalism was easier to stoke up than to contain.
But the nationalist angle was only one dimension of the Hibiya riots. The rioters were not just upset over Japan being denied its place in the sun but were also expressing a good deal of discontent over the burdens placed on Japan by the war. The Japanese financed the war through a mixture of foreign loans but also a very ruthless taxation of its population. One of the more onerous burdens for Tokyoians was that the taxes led to an increase in street tram fares. The prices for various staples also went up due to wartime taxes and the wider reverberations of the war economy on the public. The lack of an indemnity, which was one of the adamant positions of the Russian negotiators, provided a good deal of kindling for urban discontent and grievances. The Hibiya riots ushered in a period of urban disturbances and riots within Tokyo that often centered on the unfairness of the new modern economy and the escalating costs of living.
This economic discontent gives focus to the targets of the rioters. The Hibiya rioters destroyed a number of police koban boxes and other symbols of the Meiji state. While such behavior is common in urban rioting there were also portents that the rioters desired a more thorough change of the Meiji government. A number of rioters chanted slogans like down with clique government, called for the resignation of the cabinet, and some sort of contrition from the imperial house and government for police crackdowns on the rioters. The dissatisfaction of Tokyoites with the Meiji system of government in which a rotating set of genro oligarchs governed the country would become more apparent in later riots such as the 1918 rice riots. But there were signs of popular dissatisfaction with the Meiji system as early as 1905. Some of this dissatisfaction filtered into various popular nationalist societies, but some of it was also channeled into democratic and labor movements. The increasing salience of purportedly undemocratic or unconstitutional actions of the government among the rioters' grievances in the post-1905 riots was a symptom of larger discontent with the Meiji system. This was one of the factors that enabled what historians have labeled the period of "Taisho democracy" in which parliamentary governments took the reins of power from the last genro (who were also dying out by this point). The Taisho period was not an exemplar of democratic governance. The franchise was sort of expanded yet the autocratic elements of the Meiji constitution remained intact. By the same token, the internal politics of the parliamentary parties like the Seiyukai rivaled that of the Meiji oligarchs for their opaque factionalism and cliquishness.
Yet the importance of Taisho democracy as well as other components of the post-1905 period is that they show that Japan was not a predetermined path of hypernationalism and militarism. The Hibiya riots did have a nationalist strain to them, but there were also rioters who were upset that the government could not meet the needs of the people. Japanese peace societies and other groups looked askance at the fact that after such sacrifices the Meiji government was considering another round of expensive naval construction to meet the threat of the United States. Some of the impulses behind the riots became channeled into decidedly non-militarist causes such as democratic and peace societies as well as the Japanese labor movement. Although it is tempting to draw a straight line between some of the rioters' call for a renewed war and the militarism of the 1930s, Japanese history after the war proceeded in a much more crooked trajectory.
Sources
Dickinson, Frederick R. World War I and the Triumph of a New Japan, 1919-1930. Cambridge: Cambridge University Press, 2015.
Gordon, Andrew. Labor and Imperial Democracy in Prewar Japan. Berkeley: University of California Press, 1991.
Lewis, Michael Lawrence. Rioters and Citizens : Mass Protest in Imperial Japan. Berkeley: University of California Press, 1990.
I would also check out Gordon's contribution on the Hibiya Riots on MIT's Visualizing Cultures which has a good selection of primary sources on the riots as well as an essay framing these sources and their wider context.
