The 'Twenty-One Demands' emerged in early 1915 during a critical phase of Japan's imperial expansion in East Asia. Following the end of the First Sino-Japanese War and the Russo-Japanese War, Japan sought to leverage its newfound military and political power. The context was marked by China's vulnerability due to internal strife, including the effects of the fall of the Qing dynasty and the rise of warlord factions. Japan aimed to secure benefits from China by asserting its dominance and ensuring that Western powers would recognize its claims.

The demands were structured in several categories, ranging from territorial concessions to economic rights. Notably, one of the key requests involved the acknowledgment of Japanese control over Shandong Province, which had been taken from Germany following World War I’s onset. Additionally, Japan sought to secure rights to develop Chinese resources and establish greater military influence in the region. This aggressive diplomatic move was seen as an attempt to transform Japan into a regional hegemon, especially against a backdrop of potential competition with Western powers.

The response from China was mixed; while there were initial consultations and negotiations, the Chinese leadership struggled to respond cohesively to the overwhelming pressure from Japan. Popular sentiment in China was largely against the encroachment of Japanese demands, igniting nationalist feelings and leading to widespread protests. The eventual rejection of key demands, such as those that infringed on China’s sovereignty, further exacerbated tensions between Japan and China, marking a critical moment in early 20th-century Sino-Japanese relations.