Japanese and Chinese experts held a low-key event Tuesday to mark the 35th anniversary of a bilateral treaty of peace and friendship more than two months after the actual date because of the dispute over the Senkaku Islands.

The closed-door symposium in Beijing was attended by people from friendship associations of the two countries, including Uichiro Niwa, who was Japan’s ambassador to China from 2010 to 2012.

Due to the strained diplomatic relationship, no official events were held in Beijing on Aug. 12, the anniversary of the treaty signing.

Then in late September, the China-Japan Friendship Association, led by former Chinese State Councilor Tang Jiaxuan, communicated to its Japanese counterpart its intention to finally hold a ceremonial event.

Nevertheless, the Chinese side said it did not want to make the event open to the public or media, according to sources familiar with the matter.

The Japanese group’s chief is Koichi Kato, a one-time senior member of the Liberal Democratic Party, Prime Minister Shinzo Abe’s party.

China’s decision to finally hold the event could signal a less strident policy toward Japan. Bilateral ties sank to their lowest point in years when the Japanese government effectively nationalized the Senkaku Islands in September 2012.

China steadfastly maintains its claims to the islands in the East China Sea and issues concerning their sovereignty remain delicate, especially at home, for the new government under President Xi Jinping.

The friendship treaty was signed in 1978, six years after Tokyo and Beijing normalized diplomatic ties.

The pact stipulates that the two countries will develop relations based on the principles of “mutual respect for sovereignty and territorial integrity, mutual nonaggression, noninterference in each other’s internal affairs, equality and mutual benefit and peaceful coexistence.”

It says that the two countries “in their mutual relations (shall) settle all disputes by peaceful means and shall refrain from the use or threat of force.”