China and Japan are respectively the world's secondandthirdlargest economies. In 2008, China-Japan trade grew to $266.4 billion, a rise of 12.5 percent on 2007, making China and Japan the top two-way trading partners. China was also the biggest destination for Japanese exports in 2009. The relationship between China and Japan has been  _ at times by Japan's refusal to acknowledge itswartimepast to the satisfaction of China. China joined other Asian countries, such asSouth Korea,North KoreaandSingapore, in criticizing Japanese history textbooks that whitenJapanese war crimesinWorld War II. They claimed that the rise ofmilitarismbecame evident in Japanese politics. Muchanti-Japanese emotion has risen, because of the increasing feelings ofChinese nationalismand former Prime MinisterJunichiro Koizumi's visits to theYasukuni Shrine . Although Koizumi openly declared---in a statement made on April 22, 2005 in Jakarta--- "deep regret" overJapan's wartime crimes, many Chinese observers regard the apology as insufficient and not consistent with the action. Sino-Japan relations changed slightly after Shinzo Abebecame thePrime Minister of Japanin September 2006, and a joint historical study conducted by China and Japan released a report in 2010 which pointed toward new agreement on the issue ofWorld War II-era violent action. However, there also remains the dispute  over the Diaoyu Islands, which resulted in clashes between Taiwanese (Chinese) protesters and the Japanese government in April 2005. The incident led to anti-Japanese protests and violence across Mainland China, from BeijingtoShanghai, laterGuangzhou,ShenzhenandShenyang. In August 2012, Hong Kong activists landed on one of the disputed Diaoyu Islands, and Japanese nationalists responded by landing on the island the following week. The incidents set off the largest-scale anti-Japanese protests in China for decades in which protesters vandalized Japanese shops and cars. On the 14th of September relations worsened even further in response to Japan's announcement of plans to buy the island from its private owners. The news resulted in the Chinese government sending six surveillance  ships to the islands and further anti-Japanese protests in which protesters attacked the Japanese embassies in Shanghai and Beijing. What was the Chinese government's response to Japan's plans to buy Diaoyu islands?
It sent activists to Diaoyu islands. It attacked the Japanese embassies. It sent surveillance ships to the islands. It vandalized Japanese shops and cars.