The ruling Liberal Democratic Party was on edge despite securing an 80-percent success rate in the Diet by-elections on April 23.

Some of the LDP victories were far closer than expected.

But what was most upsetting for the ruling party was its loss to Nippon Ishin no Kai (Japan Innovation Party) in Wakayama Prefecture.

Yumi Hayashi, 41, of Nippon Ishin, won the Lower House seat for the Wakayama No. 1 district, giving the opposition party its first Diet seat in Wakayama Prefecture, close to its stronghold in Osaka Prefecture.

Wakayama Prefecture is traditionally considered a bastion of conservatives. Its apparent shift to Nippon Ishin cemented fears within the LDP that the Osaka-based party is becoming a serious threat to the LDP’s dominance.

Hirofumi Kado, 57, a former Lower House member, ran on the LDP ticket in Wakayama Prefecture.

The LDP went all out to support Kado, even enlisting help from Wakayama Governor Shuhei Kishimoto, a five-time Lower House member from the Wakayama No. 1 district, who belonged to the opposition Democratic Party for the People.

Komeito, the LDP’s junior coalition partner, also backed his candidacy.

Prime Minister Fumio Kishida traveled to Wakayama for the second time on the final day of campaigning to stump for Kado.

And in an exceptional move, Tokyo Governor Yuriko Koike, special adviser to the regional party Tomin First no Kai (Tokyoites First), campaigned for Kado.

Koike is close to former LDP Secretary-General Toshihiro Nikai, who is elected from Wakayama Prefecture.

Still, Kado ended up with 55,657 votes, about 6,000 fewer than Hayashi’s total.

Hiroshige Seko, acting president of the LDP’s Wakayama prefectural chapter and secretary-general for the party's Upper House caucus, said the loss is another wake-up call for the LDP.

“We want to immediately study how to re-establish ourselves, taking this as a challenge for our party’s bloc in the Kinki region as a whole,” he said April 23, referring to the region that includes Osaka, Wakayama and Nara prefectures.

In Nara Prefecture, Makoto Yamashita won the gubernatorial election on April 9, becoming the first governor backed by Nippon Ishin outside Osaka Prefecture.

In the April 9 unified local elections, Osaka Ishin no Kai, a regional party, secured a majority of seats in the Osaka municipal assembly for the first time and also maintained its majority in the Osaka prefectural assembly.

At a meeting of the LDP’s Nikai faction on April 20, Bunmei Ibuki, former Lower House speaker, sent a warning to party members.

“Nippon Ishin is gaining ground fast and furious,” he said. “Today’s political landscape is closely akin to the eve of when we lost power (in 2009).”

In the Yamaguchi No. 2 district of the Lower House, Nobuchiyo Kishi, 31, son of former Defense Minister Nobuo Kishi, won with 61,369 votes. But his rival, independent Hideo Hiraoka, 69, was only 6,000 votes behind.

“We formed a rock solid base of conservative supporters during the Abe administration, but those supporters are clearly distancing themselves (from the LDP) under the Kishida administration,” said a senior LDP official.

LDP officials were also shocked by the uphill battle in the Lower House by-election in the Chiba No. 5 district, an urban constituency close to central Tokyo with many unaffiliated voters.

The by-election was called after LDP Lower House member Kentaro Sonoura resigned over a violation of the Political Fund Control Law.

But LDP officials initially expected an easy victory for party candidate Arfiya Eri, partly because five of her six opponents were supported by different opposition parties.

Eri, 34, garnered 50,578 votes, only about 5,000 more than her closest rival, Kentaro Yazaki, 55, from the main opposition Constitutional Democratic Party of Japan.

The LDP, whose traditional power base is in rural areas, considered the Chiba No. 5 district as a touchstone of its performance in the next Lower House election because the number of urban constituencies will increase through redistricting.

“Unaffiliated voters are drifting away to other parties,” a senior Komeito official said, referring to the tight races the LDP fought in the by-elections. “That is partly because LDP candidates are decided based on politics within its prefectural chapters, rather than policies to promote young people and women.”

The LDP candidate won the Upper House constituency in Oita Prefecture, but the closeness of that by-election also upset LDP campaigners.

In the Yamaguchi No. 2 district, hereditary politics, most closely associated with the LDP, was an election issue because Nobuchiyo Kishi was seen as succeeding the constituency from his father.

“If we simply continue old-style politics, the administration could be overturned at a stretch if there is something that serves as a trigger,” a midranking LDP official said. “A crustal movement is quietly occurring. (The by-elections) revealed distrust in conventional politics.”

Just a month ago, some senior LDP officials, emboldened by recovering approval ratings for the Kishida Cabinet, said it was time for the prime minister to call a snap election.

But a former Cabinet minister said it would now be difficult for Kishida to dissolve the Lower House.

“(The by-elections) made it clear that some LDP supporters are taking a harsh view of the Kishida administration,” the source said. “We will also probably see a backlash within the LDP.”

Kishida on April 24 said he is currently not thinking about a snap election.

“All I have to do is to move important policies forward one by one, listening to the voices of the public, and deliver results,” he told reporters.

(This article was compiled from reports by Kohei Morioka and Shinichi Fujiwara.)