"It is a signal of great support to Russia," said Xing Guangcheng, a senior scholar at the Chinese Academy of Social Sciences.

Hu's tightly-scheduled weekend visit, which follows his attendance at the 60th anniversary of Russia's Victory Day five years ago, focused primarily on activities commemorating the role that Soviet Union and veteran soldiers played in WWII.

"It carries the signal that China firmly recognizes the Soviet Union's contribution (in WWII), and China will never forget the role the Soviet Union played in helping shorten China's War of Resistance against Japanese Aggression," Xing said.

The progress of the Great Patriotic War and China's War of Resistance against Japanese Aggression (1937-45) were linked.

The huge sacrifices China made in the Asian battlefield greatly contained Japan's military's muscle from extending to the European theater of operations, which helped the Soviet Union win the war against Nazi Germany.

The former Soviet Union sent troops to the Northeast China battlefront in August 1945, and the level of the two countries' military cooperation began to accelerate since then. 

According to Sergei Luzyanin, deputy director of the Institute of Far Eastern Studies at the Russian Academy of Sciences, Hu's visit means China not only values the present but also history, and cherishes the hard-won victory of WWII and, most importantly, attaches great importance to the fact that the former Soviet Union and China were allies during the war.

"It shows China's will to promote Sino-Russian cooperation on historical issues and their strategic partnership," Luzyanin was quoted by Xinhua News Agency as saying.

The coordination and friendship between China and Russia built in that period has been turned into fruitful cooperation in the economic, political and cultural spheres, Luzyanin said.

Chinese Foreign Minister Yang Jiechi said in March that bilateral ties between China and Russia have set a model for big-power relations.

"Russia has always given priority to China in its overall foreign policy. With similar global strategies, the two countries often hold the same view and have close interaction and coordination on global affairs," said Wang Haiyun, a former military attach at the Chinese embassy in Russia.