Japan’s fringe far-right party Sanseito emerged as a surprise force in the country’s upper house elections on Sunday, securing 14 seats amid rising populist sentiment and public dissatisfaction with the ruling coalition.

The party, which ran on a “Japanese First” platform, gained momentum with its hardline stance on immigration, promises of tax cuts, and pledges to boost welfare. Sanseito now holds 15 seats in the 248-member upper house, a sharp increase from the single seat it held since 2022. In the more powerful lower house, the party continues to hold three seats.

Led by 47-year-old Sohei Kamiya, a former supermarket manager and English teacher, Sanseito has built its presence largely through social media. The party’s official YouTube channel boasts over 400,000 subscribers — the largest following of any political group in Japan, and more than triple that of the ruling Liberal Democratic Party (LDP).

Sanseito’s rise comes as Prime Minister Shigeru Ishiba’s LDP and coalition partner Komeito lost their majority in the upper house. The ruling bloc had already suffered a significant setback in the lower house elections last October, leaving it increasingly reliant on opposition support.

“The phrase ‘Japanese First’ was meant to express rebuilding Japanese people's livelihoods by resisting globalism,” Kamiya said in a post-election interview with Nippon Television. “I am not saying that we should completely ban foreigners or that every foreigner should get out of Japan.”

However, the party’s campaign rhetoric — including warnings of a “silent invasion” by immigrants — has drawn criticism for being xenophobic and discriminatory. Japan’s foreign-born population reached a record 3.8 million last year, accounting for just 3 percent of the total population — far below levels seen in Europe and the United States.

Despite this, the issue of immigration has gained renewed political traction. Days before the vote, Ishiba’s administration launched a new task force aimed at curbing crimes allegedly committed by foreign nationals. The LDP also vowed to achieve “zero illegal foreigners,” a move seen by analysts as a bid to neutralise Sanseito’s growing influence.

Political observers say Sanseito has tapped into growing public discontent over economic stagnation, rising prices, and a weakening yen — factors that have made Japan more attractive to foreign tourists, but increased the cost of living for locals.

“Sanseito has become the talk of the town, and particularly here in America, because of the whole populist and anti-foreign sentiment,” said Joshua Walker, president of the Japan Society in New York. “It’s more of a reflection of the LDP’s weakness than the strength of Sanseito.”

In pre-election polls conducted by NHK, immigration ranked joint fifth among voter concerns at just 7 percent. Social security and the country’s declining birthrate topped the list, cited by 29 percent of respondents, followed closely by anxiety over soaring rice prices, which have doubled over the past year.

Despite his party’s hardline positions, Kamiya has sought to moderate its image. During the campaign, he fielded several female candidates in a bid to broaden Sanseito’s appeal beyond its core base of young men. Among the winners was a Tokyo-based pop singer who goes by the name Saya.

Still, Kamiya remains a divisive figure. In 2022, he gained notoriety for suggesting the Japanese emperor should take concubines — a comment he later distanced himself from. More recently, he drew criticism for claiming that gender equality policies were a mistake that discouraged women from having children.

In an earlier interview with Reuters, Kamiya said he drew inspiration from former U.S. President Donald Trump’s “bold political style.” Sanseito has also been compared to Europe’s far-right movements, including Germany’s Alternative for Germany (AfD) and the UK’s Reform Party.

Post-election, Kamiya ruled out any alliance with the LDP and instead voiced plans to coordinate with other minor opposition parties to consolidate the populist right. “We are gradually increasing our numbers and living up to people’s expectations,” he said. “By building a solid organization and securing 50 or 60 seats, I believe our policies will finally become reality.”

Sanseito’s success underscores the shifting political landscape in Japan, where economic anxiety and frustration with mainstream parties have opened new space for fringe actors. While the party’s breakthrough remains limited in scale, analysts warn it could push national policy further to the right.