Dialogue between North Korea and Japan could be a chance for Pyongyang to blunt cooperation among South Korea, the United States and Japan.
In an interview with Arirang News, Professor Kent Calder of Johns Hopkins University said it is important for Tokyo to refrain from making any separate arrangements.
"At the heart of cooperation, of course, is ROK and the United States but as a supportive element Japan could be valuable. So I think our three countries can't afford to see North Korea drive a wedge there. That said, generally, I think some pattern of dialogue, as long as there is coordination behind the scenes among the allies is important."
Professor Calder said dialogue is key to bringing back Japanese citizens kidnapped by North Korea in the 1970s and '80s.
Five Japanese abductees were returned in 2002, but the fate of several others remains unknown.
"In other words, there could well be a Japanese citizen still alive in North Korea who never will be able to come home if there is not some process of dialogue."
Once fresh investigations begin on the Japanese abductees, Tokyo has promised to lift sanctions and to reconsider humanitarian aid to the North, reducing Pyongyang's dependence on Beijing.
Professor Calder said the possible breakthrough is also a rare diplomatic achievement for Prime Minister Shinzo Abe, under whom Japan has seen ties sour with China and South Korea.
"I think we are at a period where the Abe administration realizes that it can't be a player on Northeast Asian geopolitical issues without some kind of contact or dialogue with DPRK."
"There has been Japan-North Korea talks, and Washington has also been conducting 1.5 track informal dialogue with North Korea, doesn't that leave South Korea out of the picture?"
"Well, it's very important that South Korea not be left out of the picture. That's absolutely the case. I've said strongly for a long time that the credibility of the Korea-U.S. alliance is the cornerstone of our position in the pacific and one of the key global elements."
Professor Calder stressed the importance of dialogue, but said quiet consultations between Seoul, Washington and Tokyo must remain intact at any cost.
Hwang Sung-hee, Arirang News.