A temperamental trawler captain is at the center of an increasingly bitter row between Asia's two biggest nations, China and Japan.
The Chinese fisherman, Zhan Qixiong, stands accused of deliberately ramming his ship into a Japanese patrol boat early this month in the East China Sea.
The incident, which normally would be considered relatively minor, occurred in disputed waters near islands claimed by both nations.
Both countries are vitally interested in the potential oil and gas reserves under the water, and won't tolerate any action which appears to question the legitimacy of their claim.
The Japanese sparked the latest escalation when a court on September 18 decided captain Zhan should be held in detention for a further 10 days for more questioning. His crew of 14 has already been released.
The Chinese Foreign Ministry reacted promptly, issuing a statement on September 19 that Japan's decision has "seriously damaged Sino-Japan bilateral exchanges."
It said China has suspended ministerial and provincial-level bilateral exchanges, halted talks on increasing flights between the two countries and postponed a meeting about coal with Japan.
Ministry spokesman Ma Zhouxu promised further actions if Japan acts -- as he put it, "willfully" -- "making mistake after mistake, China will take strong counter-measures, and all the consequences will be born by the Japanese side."
Liang Yunxiang, a Japan expert at Beijing University's School of International Studies, speaking to Reuters, emphasized the gravity of the situation.
"Although this is not a new problem, it is a lot more serious than previous similar disputes. Looking at the big picture, this time the Diaoyu Islands issue is more serious, and in my opinion in the future the Diaoyu Islands issue and other ocean disputes will become increasingly grave," Liang said.
In Tokyo, a spokesman for Japanese Prime Minister Naoto Kan called for China to keep calm, calling Beijjng's moves so far "regrettable."
Mutual suspicion and distrust is never far away from Sino-Japanese relations, particularly in view of the continuing resentment over the atrocities committed by the Japanese occupiers of much of China from 1931 to 1945.
In 2005, rioting broke out in China to protest against the visit to a Tokyo war shrine by the then-prime minister. And public opinion could be easily aroused in the present case.
A popular Chinese tabloid, "Global Times," as reported by Reuters on September 20, runs a robust editorial even hinting at military action.
"China should use enough resources and force, and be prepared to sustain losses, because if we don't, Japan will go further down the path of a hard line toward China, and conflict that erupts between China and Japan will be even more intense," the editorial said.
There is also widespread wariness of China in Japan, where many see China's growing military strength and regional power as a threat to Japanese security and influence.
In this dispute, neither side has much room to maneuver, as backing down would be seen as a major loss of face.