Although media coverage of his trip to Russia has kept Japanese Prime Minister Shinzo Abe in the spotlight during the run-up to the leadership election for his Liberal Democratic Party, he failed to achieve any major breakthrough on key diplomatic matters.

Already projected to easily beat his sole rival, former Defense Minister Shigeru Ishiba, in the Sept. 20 election and remain as prime minister with support from a majority of LDP lawmakers, Abe had no concerns about being away from Japan for four days during the leadership campaign period.

"It was impossible for Mr. Ishiba to make headlines and Mr. Abe took center stage" during his visit to Vladivostok for an annual economic forum, said Itsuro Nakamura, a professor of international politics at the University of Tsukuba.

In the Russian Far East port city, Abe held a series of bilateral meetings with regional leaders, including Russian President Vladimir Putin and Chinese President Xi Jinping on the sidelines of the fourth Eastern Economic Forum.

Even before his Russia trip, Abe had another unexpected chance to demonstrate his leadership to voters in the LDP election in responding to a series of natural disasters such as a powerful typhoon that hit western Japan and a deadly earthquake that rocked Hokkaido.

But Abe's visit to the Russian Far East has not resulted in a clear diplomatic course to pursue if he does indeed win a new three-year term as LDP chief and prime minister.

One of the key issues at the Japan-China summit on Wednesday was whether Abe could agree with Xi that he would visit China on Oct. 23, when the two nations celebrate the 40th anniversary of the bilateral peace and friendship treaty that took effect on that day in 1978.

But he failed to set the date, instead merely agreeing with Xi to "accelerate arrangements" for a visit to China.

Nor was Abe able to announce any specific projects related to the "One Belt, One Road" cross-border infrastructure initiative advocated by Xi, although the Japanese leader was ready to promote bilateral economic cooperation.

Yuki Tatsumi, co-director of the East Asia Program at the Stimson Center, a Washington-based think tank, said, "Without a major announcement on some cooperative initiatives, this may not be big enough to be called an 'achievement' per se."

With Russia, there was little progress on the long-standing dispute over a group of Russian-held islands claimed by Japan off Hokkaido, even after Abe met with Putin for the 22nd time. The islands are called the Northern Territories in Japan and the Southern Kurils in Russia.

Abe might have frustrated Putin by pressing him to settle the sovereignty issue and conclude a post-World War II peace treaty, as the Russian leader abruptly proposed Wednesday that Moscow and Tokyo conclude a peace treaty "without any preconditions" by the end of the year.

His suggestion goes against Tokyo's position that a peace deal should come after a settlement of the territorial issue.

(Kunashiri Island seen from Hokkaido, northern Japan)

Some diplomatic experts pointed out that Putin may have made the comment in a bid to slow the pace of peace treaty negotiations by proposing something that Japan would not accept.

On North Korea, Abe said in a speech at the forum on Wednesday he intends to meet with leader Kim Jong Un to discuss the North's abductions of Japanese nationals in the 1970s and 1980s.

There was speculation that Kim might attend the Eastern Economic Forum to make his debut at an international event, but the Russian government announced in advance that he would not come to Vladivostok.

Nakamura said Abe may have been relieved to learn of Kim's absence. If he had joined the forum and held bilateral talks with Abe, the meeting might not have produced any tangible results on the abduction issue. Abe has made the settlement of the issue as one of his top priorities.

Tatsumi, who is also a nonresident senior fellow at the Tokyo-based Canon Institute for Global Studies, said, "Just as Japan's Russia policy has been limited by its stance on the Northern Territories, its policy toward North Korea has been constrained by the abduction issue."

Tokyo has maintained it would normalize bilateral ties with Pyongyang after resolving outstanding issues, including the North's nuclear and missile programs and the abductions of Japanese nationals.

"Unless a pathway to create some room for diplomatic maneuver can be created on the abduction issue, Japan's consultations with North Korea will never go far, regardless of who the prime minister is," she added.