JAPANESE PRIME MINISTER SHIGERU ISHIBA 鈥 REUTERS FILE PHOTO

TOKYO 鈥 Japanese Prime Minister Shigeru Ishiba said on Sunday he had decided to resign, ushering in a potentially lengthy period of policy paralysis at a shaky moment for the world鈥檚 fourth-largest economy.

Mr. Ishiba, 68, instructed his Liberal Democratic Party (LDP) 鈥 which has governed Japan for almost all of the post-war era 鈥 to hold an emergency leadership race, he told a press conference, adding he would continue his duties until his successor was elected.

Since coming to power less than a year ago, Mr. Ishiba has overseen his ruling coalition lose its majorities in elections for both houses of parliament amid voter anger over rising living costs.

Until Sunday, he had refused calls to step down following the latest of those losses in July鈥檚 upper house vote. He had focused instead on ironing out details of a trade deal with the United States on President Donald J. Trump鈥檚 tariffs, which have roiled Japan鈥檚 critical automotive industry and cast a shadow over weak growth.

鈥淲ith Japan having signed the trade agreement and the President having signed the executive order, we have passed a key hurdle,鈥 Mr. Ishiba said, his voice seeming to catch with emotion. 鈥淚 would like to pass the baton to the next generation.鈥

Concern over political uncertainty led to a sell-off in Japan鈥檚 yen currency and its government bonds last week, with the yield on the 30-year bond hitting a record high on Wednesday.

Speculation over Mr. Ishiba鈥檚 fate was stoked by the LDP鈥檚 decision to schedule a vote for Monday on whether to hold an extraordinary leadership election.

KOIZUMI, TAKAICHI AMONG POSSIBLE SUCCESSORS
While a fresh leadership race could add pain for an economy hit by US tariffs, markets are focusing more on the chance of Mr. Ishiba being replaced by an advocate of looser fiscal and monetary policy, such as LDP veteran Sanae Takaichi, who has criticized the Bank of Japan鈥檚 interest rate hikes.

Mr. Ishiba narrowly defeated Mr. Takaichi in last year鈥檚 LDP leadership run-off. Shinjiro Koizumi, the telegenic political scion who has gained prominence as Mr. Ishiba鈥檚 farm minister tasked with trying to cap soaring prices, is another possible successor.

鈥淕iven the political pressure mounting on Ishiba after the LDP鈥檚 repeated election losses, his resignation was inevitable,鈥 said Kazutaka Maeda, economist at Meiji Yasuda Research Institute.

鈥淎s for potential successors, Koizumi and Takaichi are seen as the most likely candidates. While Koizumi is not expected to bring major changes, Takaichi鈥檚 stance on expansionary fiscal policy and her cautious approach to interest rate hikes could draw scrutiny from financial markets,鈥 Mr. Maeda said.

Since the party does not have a majority in either house, it is not guaranteed that the next LDP president will become prime minister.

Whoever becomes the next leader may choose to call a snap election to seek a mandate, analysts said. While Japan鈥檚 opposition remains fractured, the far-right, anti-immigration Sanseito party made big gains in July鈥檚 upper house election, bringing once-fringe ideas into the political mainstream.

Nearly 55% of respondents to a poll by Kyodo news agency published on Sunday said there was no need to hold an early election.

Mr. Ishiba鈥檚 last act as premier will have been to finalize the trade deal with the United States last week, under which Japan pledged $550 billion of investments in return for lower tariffs from President Trump. 鈥 Reuters