The rapid rise of the far-right Sanseito party, popularly known for its 'Japanese First' slogan, has drawn significant attention following Japan’s July 2025 upper house elections. The party, which in its previous participation held only one seat in the 248-member chamber, surged to win 14 seats, cementing its place as a formidable force on the country’s political stage.

Founded during the COVID-19 pandemic, Sanseito was initially regarded as a fringe movement, buoyed by viral online videos that mixed conspiracy theories with nationalist rhetoric, notably expressing concerns about a so-called ‘foreign invasion’. The party’s online strategy, including a widely followed YouTube channel, helped it connect with disaffected voters amid nationwide economic and demographic uncertainty.

Sanseito’s 2025 election platform focused on anti-immigration policies, economic nationalism, and pledges to increase social welfare spending, such as cutting the consumption tax and increasing child allowances. These proposals resonated with younger conservatives and those frustrated by Japan’s rising prices and stagnant wages. Particularly, its tough talk on immigration found a receptive audience among voters uneasy with changes in the country’s traditionally low level of foreign residents. As of the end of 2024, immigration authorities reported a record 3 million foreign residents in Japan, representing roughly 2 percent of the population.

Sanseito’s leader, Sohei Kamiya, a former military reservist, positioned himself as an advocate against globalist influences and multinational corporations. Kamiya has publicly acknowledged drawing inspiration from international far-right figures such as Donald Trump, adopting a combative political style on issues like gender equality and family policy. At times, he has attracted controversy for statements interpreted as linking gender equality policies to declining birth rates—a view he later sought to soften, clarifying that his party does not aim to ban immigration outright.

Despite holding just three seats in the lower house and lacking numbers to propose budget bills in the upper chamber, Sanseito’s influence extends beyond its legislative presence. The party expanded its reach in urban centers like Tokyo, where high-profile candidates such as pop singer Saya secured victories, underscoring widening support among diverse conservative constituencies.

Sanseito’s breakthrough has shaken the ruling Liberal Democratic Party (LDP), which lost its upper house majority for the first time in years. Prime Minister Shigeru Ishiba remains in office to manage key negotiations, including those on trade tariffs, despite this historic setback. In an attempt to counter growing anti-immigration sentiment, the ruling coalition established a committee days before the election, aiming for “orderly and harmonious coexistence” between foreign residents and citizens—a move widely seen as too late to blunt Sanseito’s momentum.

Historically, Japan’s resistance to large-scale immigration has been reinforced by its homogenous society and apprehension over social change. However, an aging population and shrinking workforce have prompted the government to cautiously relax immigration laws. The new influx has become a flashpoint in national politics, with Sanseito blaming existing policies for social and economic challenges and pushing the LDP to consider tougher immigration stances.

Political analysts note the party’s success marks one of the most significant rightward shifts in modern Japanese politics and challenges long-held assumptions about the improbability of populist movements gaining traction in the country. Sanseito has expressed its intention to form alliances with other small parties and amplify its legislative influence in coming years. As Japan continues to grapple with demographic challenges and economic uncertainty, the rise of the 'Japanese First' party signals a new era of political contest and reorientation.