SEOUL - This week South Korean President Park Geun-hye visits Washington for talks with President Barack Obama on containing the North Korean nuclear threat and U.S. concerns over South Korea’s ongoing friction with Japan.

But South Korea’s close relationship with China is also likely to be a topic, especially after Park drew attention last month as a prominent guest at Beijing’s massive World War II military parade — one of the only leaders of a U.S.-allied nation to attend.

“When I talked to administration officials about it, I don’t sense a lot of anxiety. I think they understand what she is trying to do,” said Victor Cha, chief Korean analyst at the Center for Strategic and International Studies in Washington.

When Park meets with Obama Friday they will likely discuss whether her efforts to draw Beijing closer to Seoul and away from Pyongyang are working.

FILE - Chinese President Xi Jinping, right, applau
FILE - Chinese President Xi Jinping, right, applauds with, from left, Kazakhstan President Nursultan Nazarbayev, South Korea President Park Geun-hye and Russia's President Vladimir Putin, during a parade to mark the 70th anniversary of Japan's surrender.

Since she was elected in 2012, Park has visited China numerous times and has tried to forge closer relations through personal diplomacy and increasing economic ties.

During this same period Beijing’s relations with Pyongyang have been strained. Following North Korea’s third nuclear test in 2013, Beijing joined in United Nations sanctions imposed against Pyongyang.

Korean leader Kim Jong Un, who came to power in 2001, has yet to visit Beijing.

Closer relations

While it may appear Park’s strategy is succeeding at sidelining Pyongyang without provoking it, Michael Green, who holds the Asia and Japan chair at the Center for Strategic and International Studies, notes that Beijing continues to provide vital economic support to North Korea.

“In the actual substance of what China is doing to help on the North Korea problem, it still remains to be seen if this investment will pay off,” Green said.

Just this last weekend a Chinese delegation headed by Liu Yunshan, the Chinese Communist Party's fifth-ranked leader, attended Pyongyang's 70th anniversary of the country’s ruling workers party, in a seeming gesture of support for Kim.

During the North Korean military parade, Liu stood next to Kim and the two were shown smiling and engaging in conversations.

FILE - In an image made from video, North Korean l
FILE - In a video image, North Korean leader Kim Jong Un, center, and Liu Yunshan, China's Communist Party's No. 5 leader, second right, waves during a ceremony to mark the 70th anniversary of the country's ruling party, in Pyongyang, Oct. 10, 2015.

If Pyongyang continues to hold off on provocations such as missile tests and instead cooperates on hosting separated families reunions scheduled to start next week, pressure could grow on Seoul to split slightly from Washington and ease some sanctions on the North.

While the military alliance remains strong, with more than 28,000 U.S. troops stationed in South Korea, there are some concerns that the Park government is resisting Washington’s request to place the (THAAD) missile defense system in country so as not to alienate Beijing.

Both Washington and Seoul deny this and say there has not yet been a formal request made by the U.S. regarding THAAD.

South China Sea issue

There are also regional perceptions that South Korea does not want to align with the U.S. to criticize China for its aggressive moves in the South China Sea or human rights violations.

CSIS’s Green said while in Washington, Park should address this issue.

“Publicly, I think what would be very important for President Park is to explain a vision of the future of Asia that shows what we all know, that Korea is committed to an open order based on the rule of law and democracy and no coercion,” he said.

FILE - Former comfort woman Kil Un-ock, forced int
FILE - Former comfort woman Kil Un-ock who was forced to serve for the Japanese troops as a sexual slave during World War II, attends a rally against a visit by Japanese Prime Minster Shinzo Abe, in front of the Japanese Embassy in Seoul, South Korea.

In contrast to South Korea’s growing friendship with China is Seoul’s ongoing dispute with Tokyo over the thousands of Korean "comfort women" who were forced to work as prostitutes during World War Two.

During his speech to commemorate the 70th anniversary of the end of World War Two, Japanese Prime Minister Shinzo Abe fell short of offering an explicit apology that Park demanded he make before she will meet with him.

But Park decided to drop her demand because Abe did promise to uphold apologies by past Japanese leaders, including the 1993 Kono Statement that offered apologies and remorse to the women.

Park and Abe have agreed to meet with Chinese President Xi Jinping in a trilateral summit later this year.

But this issue continues to complicate relations between Washington’s two most important allies in Asia.

On boosting economic development, Park and Obama will likely discuss South Korea’s interest in joining the Trans-Pacific Partnership trade agreement that includes 12 Pacific nations members, including the U.S. and Japan.

But expanding the TPP membership could take years because the deal faces a long ratification process then must be implemented among the founding members before any new members can be added.