In 1920, Japan joined the League of Nations, and in 1928 they signed the Kellogg-Briand Pact renouncing war as an instrument of foreign policy.
Japan’s economy surged during the 1920s, producing genuine prosperity for most of its population for the first time. After 1929, the Great Depression hit Japan hard, as it relied on US markets to absorb most of its manufactured goods. Growing popular unrest led to a rise of right wing nationalism and the 1932 assassination of Japan’s prime minister (by a group of naval officers) ended civilian control of the Japanese government.
Japan subsequently blew up a section of the (Japanese-owned) Manchurian railroad as a pretext to invade Manchuria. Chinese leader Chiang Kai-shek appealed to the League of Nations, which called on Japanese troops to withdraw. Instead Japan left the League. In 1937, they launched an all-out war on China, deliberately targeting civilian non-combatants.Industrialization and Militarization of Japan | The Most Revolutionary Act
Once again in the present day, the Japanese Constitution forbids war as an instrument of government policy, unlike the US, which does the exact opposite.
Never ending wars are the ONLY instrument of US government, because that is what keeps billionaires in power and builds their absolutely corrupt riches even more.