Now let's look at why experts say Japan is eager to strengthen cooperation with China to boost its economy.
The dialogue was first convened in 2007 in Beijing. Japan sent 70 delegates including six cabinet members.
The second meeting was held in Tokyo in 2009. Five cabinet members and one deputy cabinet minister attended the meeting.
Many more delegates have attended this third dialogue. There are 120 delegates, including six cabinet members and three deputy cabinet ministers.
Japanese media say Foreign Minister Katsuya Okada demanded the number of delegates be reduced, but cabinet members refused, saying they wanted a wide field of discussion with China.
In June, the Japanese government made a strategic plan for its next ten-year's economic development. It outlined ways of strengthening cooperation with China in many aspects.
Japan External Trade Organization said "China's market is upgrading. People are intending to buy finer products. The change in the investment orientation is to adapt to the situation. We can make out the trend in industries such as automobile, food, public sectors and infrastructure."
The third dialogue comes as Japan's economy is getting worse. Its domestic situation is stagnant, and purchasing power is weakening.
Ke Long, Senior Fellow of Fujitsu Research Institute said "Japan didn't take active talks with China on trade and economic cooperation, especially to push forward its free trade agreement with China, because Japan doesn't want to open its agricultural market. But Japan's economic development is slowing down. The Japanese yen is increasing in value. Japan's stock market is also falling. There is a tendency of deflation. The economic situation urges Japanese government to hold this kind of dialogue with China."
Some analysts also say Japanese Prime Minister Naoto Kan is willing to relax exportation pressure as China becomes Japan's biggest importer. Kan is preparing for the upcoming party leadership election. To win the election, he has to gain support from big enterprises.