Final answer:
Japan's victory in the Russo-Japanese War was due to its modernized military and effective strategy, while Russia's loss stemmed from economic issues, poor leadership, and underestimation of Japanese capabilities, sparking internal unrest and reforms in Russia.
Step-by-step explanation:
The reasons for Russia's loss and Japan's victory in the Russo-Japanese War can primarily be attributed to Japan's effective industrialization and military strategy, compared to Russia's economic struggles and leadership issues under Tsar Nicholas II. Japan's surprise naval attack on Port Arthur and their military prowess in Manchuria showcased their organized and modernized military capabilities. On the other hand, Russia occupied Manchuria following the Boxer Rebellion and sought to expand its influence in East Asia but was unprepared for Japan's military strategy and power. The subsequent Russian defeat triggered widespread unrest within Russia and highlighted the need for economic and political reforms, leading to the establishment of the Duma. Meanwhile, Japan's remarkable victory over a major European power significantly altered international perceptions, solidifying Japan's status as a world power.