Japanese Prime Minister Shinzo Abe, and more than 1,400 representatives from both countries participated in the event, which Li said showcased a wide range of common interests shared by the two countries.
The hotline will take effect on June 8, according to broadcaster NHK. The pact provides for meetings between both nations' defence officials and a mechanism for their naval vessels to communicate at sea to avert maritime incidents.
A new chance has emerged for the improvement and development of bilateral relations, Li said, urging the two neighbors to take new steps for their ties to progress and to bolster the confidence of the two peoples and of the entire global community in the development of China-Japan relationship.
During the meeting with Abe, Li - who is on his first official visit to Japan since becoming premier in 2012 - said that the two sides should take the opportunity to get bilateral ties back on a normal track.
"China will also be able to learn from Japan's experience in finance and investment", Sun said. He is also the first Chinese leader to visit the country in 8 years.More news: Facebook bans ads on Ireland's abortion referendum by foreign advertisers
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Abe briefed Trump about the details pertaining to a summit on Wednesday with Chinese Premier Li Keqiang and South Korean President Moon Jae-in, the ministry said.
At a reception marking the 40th anniversary of the treaty in Tokyo, Li said, this is the best possible way to commemorate the signing of China-Japan Treaty of Peace and Friendship, Xinhua reported.
Relations between the two countries are "at a crucial stage to improve bilateral ties", Li told Abe, adding that the two neighbours should be partners rather than foes.
The premier called on Japan to align its development strategies with the Belt and Road Initiative, boost cooperation in innovation and high-end manufacturing.
"Cooperation will be good for both China and Japan, as long as it's honest".