billion dollar trade relationship.
CHINA-ISLAND DISPUTE - Planting the Chinese flag on a disputed island in the East China Sea. Japanese helicopters hover as this turf dispute gets ugly.
Protests in Japan, Hong Kong and Beijing as a nationalist spirit grips.
MEMBER OF THE FEDERATION FOR DEFENDING THE DIAOYU ISLANDS, SAYING:
"The hard facts prove that Japan is a monster, a devil. We must eliminate the beast in order to protect the Chinese nation."
Anger, discontent after Japan detains five members of an activist group from China, Hong Kong and Macau . Sailing from Hong Kong harbour - tracking their movements on Facebook - they landed on an island chain claimed by both China and Japan.
The island sits in a sensitive spot - lodged in between Japan, China and Taiwan.
WILLY LAM, ADJUNCT PROFESSOR, CHINA STUDIES, CHINESE UNIVERSITY OF HONG KONG, SAYING:
"From the Beijing's perspective there will be a major change of leadership coming up at the 18th Party Congress. At this stage the government also doesn't want to appear as weak. Particularly given the rise of Chinese nationalism."
Control over Asia's seaways has become one of the most contentious geopolitical issues this year.
As China's economy rises so too does its political voice.
The world's number two economy claims sovereignty over virtually the entire South China Sea. Naval boats patrolling the region.
These South Korean athletes swim to an island at the centre of a territorial dispute between Seoul and Tokyo.
Further south the Philippines stands behind its own sovereignty claims.
Diplomatic spats like this could jeopardize a huge Asia trade flow. China is the largest trading partner of both Japan and Korea.
Japan had invested about $80 billion in China up to the end of last year. South Korea $50 billion.
ADJUNCT PROFESSOR, CHINA STUDIES, CHINESE UNIVERSITY OF HONG KONG, SAYING:
"Already in China there are very emotional netizens calling for the boycott of Japanese products. I think both governments at this stage are very anxious to prevent a trade war. I think they realise very well that trade is perhaps the only positive factor in bilateral relations."
And across the region old grudges linger. Japanese ministers commemorate 67 years since the end of World War 2.
Koreans demand an apology for women forced into sexual slavery by Japan during that conflict.
More signs the forces of history still exert a powerful pull … in the new epicenter of global economic growth.
Tara Joseph reporting for Reuters.