English-language and Japanese versions of a website were launched by China on Wednesday to demonstrate its sovereignty over the Diaoyu Islands.
Experts said the move, which was announced by the State Oceanic Administration, is aimed at boosting global publicity on the issue in a reasoned manner.
Japan triggered a crisis over the islands in September 2012 when it unilaterally announced its decision to "nationalise" them, prompting a serious standoff with China and leading to Sino-Japanese relations plunging to a record low.
In December, Beijing launched a Chinese-language website covering the Diaoyu Islands issue, a move interpreted widely as a measure to highlight its sovereignty over the islands.
A banner at the top of the expanded site greets visitors with the words "Diaoyu Dao: The Inherent Territory of China" in English or Japanese, followed by the Chinese national flag.
Run by the National Marine Data and Information Service, the site now features historical records, evidence, literature and legal documents.
Yang Bojiang, deputy director of the Institute of Japanese Studies under the Chinese Academy of Social Sciences, said the site's expanded version "is of much greater significance" compared with the original, as it is far more accessible to foreigners.
"What the international community really needs is the truth and facts regarding the islands. The versions in English and Japanese present critical historical details of the Diaoyu Islands in a reasoned and acceptable way," Yang said.
The 11 maps on display date as far back as 1721. Deliberated on by ancient Chinese dynasties, Britain and even Japan, the maps show that the islands belong to China.
Zhou Yongsheng, a professor of Japanese studies at China Foreign Affairs University, said the world should be told that it was Japan, not China, that had acted provocatively toward the islands.