Japan is walking on a tightrope between its biggest trade partner China and its sole military ally, the United States, as China issue dominates the talks between Japanese Prime Minister Yoshihide Suga and U.S. President Joe Biden on Friday at the White House.

Suga is the first foreign leader to meet Biden, while four years ago, then-Japanese Prime Minister Shinzo Abe was the first foreign leader to visit Donald Trump.

During the talks, Washington and Tokyo showcased the alliance between their two countries and vowed to build a more "free and open Indo Pacific".

The two leaders said they share serious concerns regarding "human rights" in China's Hong Kong and Xinjiang. A joint statement following the talks also mentioned the importance of peace and stability across the Taiwan Straits. 

"I refrain from mentioning details, since it pertains to diplomatic exchanges, but there is already an agreed recognition over the importance of peace and stability of the Taiwan Straits between Japan and the United States, which was reaffirmed on this occasion," Suga said. 

In the United States on Saturday, the Chinese Embassy issued a statement that said the comments made by the U.S. and Japan are beyond the range of bilateral relations and the joint statement is in nature an endorsement for separatist activities. 

Chinese Foreign Ministry spokesperson Zhao Lijian said Friday that China has expressed solemn concern about the collusion between Japan and the U.S., and both Washington and Tokyo should take Beijing's concerns seriously. 

Why China issue dominates the talks? 

It has clearly been Biden's objective to make Japan a pivot country to form a so-called Indo-Pacific alliance against China, Josef Gregory Mahoney, a professor of Politics at East China Normal University, told CGTN in Memphis, Tennessee. 

"There was concern that Suga would appease Biden and take a harder stance towards China. I think what we really saw was him simply saying that there was a desire to peacefully maintain the status quo, which is really nothing new," said Mahoney.

The professor said he thinks that Suga clearly wants to avoid antagonizing Beijing but at the same time be gracious to his host the White House. 

CGTN correspondent Terrence Terashima said in Tokyo that China is a very important economic partner for Japan and Japan also has its regional security concerns which need support from the U.S. 

Suga wants to keep a two-pronged approach with China on regional security issues and economic cooperation, he added. 

Terashima went on saying that Japan wants to play a more low-key role on Taiwan issue. There was some disappointment that Suga didn't prove his diplomatic skills as his predecessor Shinzo Abe in the approach with the U.S., he added. 

U.S. and Japan's common interest with China 

The U.S. and Japan said in the joint statement that the two countries recognized the importance of candid conversations with China, reiterated their intention to share concerns directly, and acknowledged the need to work with China on areas of common interest. 

Mahoney said their common interests with China include combating climate change, and to a certain extent, cooperating on COVID-19 recovery.  

"I think they will both like to see or at least to prevent more deterioration in economic relations. Certainly that is the case from Japan with China being its largest trade partner," said the professor. 

Fukushima nuclear-polluted water unmentioned 

The joint statement between Biden and Suga concerns many ocean-related issues, but leaves out the recent hotspot issue of Japan's plan to discharge contaminated water from Fukushima nuclear station by releasing it into the Pacific Ocean. 

What's interesting is that the Fukushima release hasn't received much discussion in mainstream U.S. media. And the coverage we have seen has emphasized the Japanese position that the move is not a significant environmental danger, said Mahoney. 

No reporter raised the topic in the joint presser neither did Biden. Instead Suga mentioned supporting Biden's call for decarbonization and other climate change combat efforts.  

"I think he effectively grinned his comments and perhaps to distract people from the Fukushima issue," said Mahoney. 

Climate change, DPRK and Olympics 

On another of his key priorities, Biden said he and Suga agreed on the need for "ambitious climate commitments" and indicated that both nations would soon announce goals by 2030. 

Biden will lead a virtual summit next week in hopes of rallying greater commitments on climate. 

"We confirmed that Japan and the U.S. will lead global decarbonization," Suga said. 

Biden and Suga also discussed next moves on the Democratic People's Republic of Korea (DPRK). The U.S. has said it is in the final stage of a review of policy towards the country. 

Suga said that Japan, a prime target for the DPRK, wanted the complete, verifiable and irreversible dismantlement of DPRK's weapons of mass destruction and ballistic missiles. 

He also told Biden that he was committed to moving forward with the summer Olympic Games in Japan and Biden offered his support.