The Sino-Japanese relations consist of contradiction, harmony and frictions as well as cooperation. As China's reform and opening-up drive enters the 31st year, one can say basically the "Japan factor" has had a positive and constructive overall impact on China's reforms.

There is no doubt China achieved fast development since it started the reform and opening-up by mainly tapping into its own strengths, which means the nation's "internal factors" have been the driving force behind the great success. At the same time it is also necessary to evaluate the role that foreign influences, or "external factors", have played in China's reform and openness. This article discusses the role the "Japan factor" has played in China's fast development since the reform began.

First, in the past 30 years of reform and opening-up the "Japan factor" has played a basically positive role in China's fast development.

When China launched its reform and opening-up, it badly needed a peaceful and stable surrounding environment that allowed it to focus on economic construction. It so happened that China and Japan signed the Peace and Friendship Treaty in the same year, which means the desire to end the "abnormal state" of bilateral ties between the two neighbors, or the "state of war", expressed in the China-Japan Joint Communiqu of 1972, officially became law. It also ushered in a new era of peaceful coexistence between China and Japan.

The significance of the Peace and Friendship Treaty also lies in the fact that the two nations reached a consensus on opposing hegemony, a concept that has worked positively for China to earn a perimeter of security around its territory.

Second, the Japan factor, out of all foreign influences, has been enjoyed top priority in China's economic exchanges with the outside world ever since the reform and opening drive started.

Non-official and "semi-official" trade between China and Japan began as early as the 1950s. And from 1966 to the mid-1980s Japan was China's No 1 trading partner for nearly 20 years. The following seven years saw Sino-Japanese trade overtaken by the country's trade with Hong Kong (under British rule at that time) in terms of total value.

In the 1990s a virtuous cycle in which bilateral trade and direct Japanese investment in China boosted each other took hold as direct investment in China by Japanese enterprises grew fast. Between 1993 and 2002 Japan regained and occupied the spot as China's top trading partner for a decade.

Not counting Hong Kong, Japan led China's foreign trade partners for 25 years out of the past 30 in terms of annual value and was replaced by the US only in the last five years.

The growth of China-Japan trade and investment in China by Japanese enterprises has made Japan the leading supplier of production technology to China on the one hand and a key export market for Chinese industries on the other. Meanwhile, China has become an important export market for Japan as well. The country's export to China in July 2008 surpassed that to the US for the first time and China is now the largest market for Japan's export trade.

This means the "Japan factor" has played a positive role in China's sustained development as well as reform and opening; while the "China factor" has become more important than ever to Japan's economic development. It also constitutes the vital foundation for the two neighboring countries to construct the strategic relationship of mutual benefit.

Third, the Japan factor served as the most important source of positive experiences and negative lessons for China as the latter learned from foreign countries' successes and failures in economic development.