For much of the past two months, ever since the historic loss of Japan's LDP in July's parliamentary elections, we have mocked the highly unpopular Japanese PM Shigeru Ishiba, who was clinging to the post despite record disapproval and a clear shift in popular sentiment that had clearly stripped him of mandate to be Japan's leader. 

A few hours ago, Ishiba finally decided to prove us wrong and announced he will step down - following weeks of calls for his departure - a decision that will set in motion a leadership race that may generate concerns for investors. 

“While I feel there are still things I wish to do as premier, I have made the difficult decision to step down,” Ishiba said at a press conference in Tokyo on Sunday. “Having seen the US trade negotiations through, I felt that now is the right time to stand down and give way to my successor.”

“I felt that if I continued amid a vote on an early leadership race, it could have created an irreversible division within the party, which is certainly not my intention.” He will stay on as prime minister until his successor takes over.

Ishiba’s resignation brings to an end a tenure marked by humiliating election results that stripped the Liberal Democratic Party’s ruling coalition of its majorities in both chambers of parliament and left market participants unsure of Japan’s fiscal plans. His departure is likely to fuel uncertainty among investors over the coming weeks until a new leader is chosen. It will also likely spark debate among market participants whether his replacement will follow through with the trade deal that Japan reach with Trump.

As Bloomberg warns, the risk of further instability could weigh on the yen and longer-term bonds when trading opens Monday in Asia. Japan’s currency was one of the weakest performers among its Group of 10 peers last week, while yields on longer-term Japanese government debt reached fresh multi-decade highs.

“Prime Minister Ishiba was known for his strict stance on fiscal discipline,” said Katsutoshi Inadome, senior strategist at Sumitomo Mitsui Trust Asset Management, flagging the likelihood of upward pressure on super-long yields. “While it remains unclear who will become the next prime minister, it’s difficult to envision anyone with a fiscal discipline stance better than or even equivalent to his.”

Which, in a country best known for the short tenure of its prime minister, more easing to placate the masses is on deck, even if it means another surge in inflation, and even higher prices in gold and crypto as the local population protects what little is left of its purchasing power.

The LDP was set to hold a vote Monday if it should bring forward a leadership election by two years, but that had looked increasingly likely to turn into a vote of no confidence in the premier. That vote will now be canceled, and instead the LDP will hold a leadership race, Ishiba said.

Lawmakers jockeying to position themselves as the next premier will need at least 20 other members of parliament to support their candidacy in order to enter the race. Whoever emerges top in the party contest will then have to win a vote in parliament to become prime minister in a fractured Diet.

Potential candidates within the ruling party include Sanae Takaichi, 64, a former internal affairs minister who finished second to Ishiba in an LDP leadership race last year. If chosen, Takaichi would be Japan's first female prime minister.

A party veteran who has held a variety of roles, including economic security and internal affairs minister, she is known for conservative positions such as revising the pacifist postwar constitution; Takaichi is a regular visitor to the Yasukuni shrine to honor Japan's war dead, viewed by some Asian neighbors as a symbol of past militarism.

She is a fan of Abenomics economic policies and favors stimulus measures which means any hope for a rate hike by the "independent" Bank of Japan would be quietly put to pasture under her leadership (we leave the discussion of BOJ "independence" to an other time). 

A member of Japan’s largest nationalist organisation Nippon Kaigi and known as a hard-line conservative, Takaichi opposes same-sex marriage and supports a requirement for couples to share a surname after marriage. She has also stated that a government gender equality plan could "destroy the social structure based on family units" has voiced opposition to proposals to change the law so that a woman could become the Emperor of Japan.

Takaichi supports imprisoning those who damage Japan's national flag, and is considered a China-hawk when it comes to foreign policy and supports revising article 9 of the Japanese constitution which prohibits Japan from entering armed conflict.  She’s also a vocal critic of Chinese economic practices such as intellectual property theft and calls on Japan to lessen its economic dependence on China.

Most notably, she believes that immigration to Japan risks destabilizing Japanese society and argues that Japanese heritage must be protected. As such, should she replace Ishiba, she would become the latest hard-line conservative to take charge in blowback to the catastrophic policies unleashed by the liberal left in recent years.

Among other possible candidates, Takayuki Kobayashi, a former economic security minister, is on the right-wing of the party and would be a possible rival to Takaichi in garnering support from that section of lawmakers. Yoshimasa Hayashi, the current chief cabinet secretary, as well as Finance Minister Katsunobu Kato, might also show interest in succeeding Ishiba. 

“If Ms. Takaichi is appointed, bond selling could intensify due to the risk of a credit rating downgrade,” Sumitomo Mitsui Trust’s Inadome said. In that scenario, “we could see a triple dip: falling bond prices, a weaker yen, and declining stock prices.” 

A Koizumi or Hayashi win is more likely to return the yield curve to its previous shape, he added.

Traditionally, the LDP’s dominance in parliament all but assures that its leader will become prime minister. With no majority in either house, there’s only a slim chance the leader of the LDP could fail to clinch the premiership, though that decision is still some weeks away.

The next premier will have to navigate challenges ranging from global trade headwinds to simmering resentment at home over soaring costs of living. Ishiba had called for fresh cash handouts to support consumers, while opposition parties sought tax cuts or higher spending, proposals that have given investors cause for concern.

In the press conference held Sunday, Ishiba said that consumers and businesses will need more support and pressed the need to maintain momentum for wage hikes. He indicated that he essentially decided to step down following the July election setback, but saw a need to make more progress on the trade deal with the US first.

US President Donald Trump signed his trade agreement with Japan and put it into effect with an executive order on Thursday. Although current tariff rates will be lowered with the new order, Japan will still have to pay a maximum 15% tariff on its products, including exports of cars and auto parts.

Still, the signing of the deal leaves Ishiba with some kind of legacy to walk away with after a troubled year at the helm.