The Liberal Democratic Party-Komeito coalition's failure to retain its Lower House majority in Sunday’s general election begs the question — will Shigeru Ishiba remain as prime minister?

Under Japan’s parliamentary system, lawmakers vote for who among them should be the country's head of government. If the two chambers of parliament choose different lawmakers, the vote of the more powerful Lower House will supersede that of the Upper House.

This typically means that the president of the party that holds the majority in the Lower House, or that of the larger party in a coalition with control of the chamber, becomes the prime minister. Such was the case on Oct. 1, when Ishiba, having emerged victorious in the LDP presidential election a week earlier, was voted into the position.

However, in the wake of Sunday’s general election, the LDP and Komeito find themselves with just 218 seats, including three LDP members who were not endorsed by the party — short of the 233 needed for control of the 465-seat Lower House. As such, there is no guarantee that Ishiba has the numbers to remain as prime minister.

Nevertheless, it doesn’t mean that the largest opposition party, the Constitutional Democratic Party of Japan (CDP), has enough votes of their own to elect party chief Yoshihiko Noda into power. The CDP secured 148 seats on Sunday.

So what happens now that no single party or coalition has a majority?

A special session of the Diet, the formal name of the national legislature, will be convened in mid-November for a ballot to elect the prime minister. Lower House rules stipulate that when no single lawmaker has the majority of votes, a runoff will be held between the two top candidates — most likely Ishiba and Noda.

Four runoffs have taken place in the past. In the most recent one, in 1994, Tomiichi Murayama, leader of the Japan Socialist Party (JSP) — the second-largest party at the time — went up against Toshiki Kaifu, who was backed by the Shinseito and Komeito parties.

Murayama was ultimately elected as prime minister with the support of the LDP and New Party Sakigake, which formed a tripartite coalition with the JSP.

This time, both the LDP and CDP are looking to get Nippon Ishin no Kai and the Democratic Party for the People (DPP) on their respective sides. The two smaller parties hold 38 and 28 seats, respectively.

For the LDP-Komeito bloc, support from either of these parties will be enough for it to secure a Lower House majority.

The government and ruling coalition are reportedly planning to convene the special Diet session to choose the prime minister on Nov. 11 — a few days later than the initial date of Nov. 7, likely to buy time to secure votes.

During a TV program on TBS on Monday evening, DPP chief Yuichiro Tamaki confirmed that party members voting for someone other than him in a runoff is an option. And at a news conference on Tuesday, he suggested that his party is open to discussions.

"If there are efforts (from other parties) ... I would be in communication with them," he said, adding that no negotiations were currently underway.

The CDP meanwhile, is reaching out to Nippon Ishin and the DPP. Technically, if all of the opposition votes go to Noda, he will have the numbers to win. However, this scenario is unlikely given that the opposition parties were not even able to coordinate to field unified candidates against the LDP and Komeito during the general election.

In the end, Ishiba is still more likely to win a runoff and remain as prime minister — at least, for now.