Japan and China have decided to craft a major political document that will lay the foundation for the two countries’ future relations and are likely to unveil it when Chinese President Xi Jinping visits Japan as a state guest in the spring, sources close to the matter said Thursday.

Prime Minister Shinzo Abe and Xi agreed to create the document, the fifth of its kind since the countries normalized diplomatic relations in 1972, during a meeting in December in Beijing last year, the sources said.

While relations between Japan and China have often been frayed by differing views of wartime history and territorial disputes, ties have improved in recent years amid Beijing’s trade spat with the United States.

To start the drafting process for the document, Vice Foreign Minister Takeo Akiba will visit China, possibly on Monday, one of the sources said. Another said the document will likely include a reference to the “responsibility” both countries should bear to maintain peace and stability in East Asia.

Four political documents are currently considered to be the foundation of Japan-China relations.

The first, a joint communique signed in 1972 between Prime Minister Kakuei Tanaka and Chinese Premier Zhou Enlai, ended the “abnormal state of affairs” between the countries following the end of World War II and resulted in China renouncing its demand for wartime reparations.

The second, a peace treaty concluded in 1978, affirmed the countries would settle all disputes by peaceful means and refrain from using force, while the third was created when Chinese President Jiang Zemin visited Japan as a state guest in 1998.

The fourth, created when Xi’s predecessor, Hu Jintao, visited as a state guest in 2008, said the countries would promote a “mutually beneficial relationship based on common strategic interests.”

Japan, for its part, is likely hoping the drafting of a new document will help keep China committed to the international rule of law and rein in its economic and military expansionism. It will be looking to cover environmental issues and North Korea’s nuclear program in the upcoming discussions.

But the drafting process could be complicated by outstanding differences, including China’s dispatch of government ships to waters near the disputed Senkaku Islands. The islets in the East China Sea are controlled by Tokyo but are also claimed by Beijing, which calls them Diaoyu.

The countries are also at odds over China’s detainment of Japanese nationals who, Tokyo argues, are being held on unclear charges.

While Abe has been eager to invite Xi as a state guest, some conservative lawmakers in his Liberal Democratic Party have pushed for the trip to be canceled, citing such outstanding issues as well as the human rights situations in Hong Kong and the far-western Xinjiang region.

Japan is hoping to avoid using keywords espoused by Xi — such as the Belt and Road initiative and the concept of a “community of shared future for mankind” — in the new document out of concern it will give the impression China had taken the lead in its creation.