Japan and China signed $2.6 billion in business deals and touted their warmer ties on Friday during a rare visit to Beijing by Japanese Prime Minister Shinzo Abe as both face trade challenges from US President Donald Trump.
Relations between Asia's two biggest economies have improved in recent years after they sunk to new lows in 2012 when Tokyo "nationalised" disputed islands claimed by Beijing.
Addressing a joint press conference, Abe said that the two leaders had agreed to "play a constructive role for the sake of this region's peace and prosperity".
"I believe active trade will deepen ties between Japanese and Chinese peoples further," he said.
"Now, international conditions are unstable, and uncertainties have increased," Li said, adding that the countries' economic cooperation would "benefit the development of global free trade".
The relationship has rapidly warmed up as Trump has slapped massive tariffs on China while also targeting Japanese exports in his effort to cut US trade deficits, despite touting his personal bonds with Abe and Chinese President Xi Jinping.
Abe travelled with nearly 1,000 delegates from Japanese companies, who struck 500 deals worth a total of $2.6 billion, Li said, without providing details.
The companies are eager for increased access to China's massive market, while Beijing is interested in Japanese technology and corporate know-how.
"Though the US is quite an influential factor in China-Japan ties, the effect is limited," China's nationalistic Global Times said in an editorial.
"If Beijing and Tokyo intend to plan their future bilateral relationship based on Washington's attitude, they will only get lost," the state-run daily said.
The two leaders also oversaw the signing of several political agreements, including a currency swap deal and a mechanism to avoid accidental clashes between their militaries which often come in contact in the disputed East China Sea.