TOKYO, Sept 27 (Reuters) - Some Chinese customs offices have started stricter checks on shipments to and from Japan, causing delays, in what may be retaliation against Japan's recent detention of a Chinese fishing boat captain, the Mainichi newspaper said on Monday.
Fishing trawler captain Zhan Qixiong was released and arrived back in China on Saturday after his boat collided with Japanese patrol ships on Sept. 7 near disputed islets, known as the Diaoyu in China and Senkaku in Japan.
China demanded an apology and compensation from Japan, which Japanese Prime Minister Naoto Kan rejected, illustrating the fragility of ties between Asia's two biggest economies troubled by Chinese memories of wartime occupation, military mistrust and maritime territorial disputes.
Customs authorities in Shanghai on Sept. 21 notified a Japanese major transport company that they would sample check all air cargo instead of the usual 30 percent, the Mainichi said, citing unidentified sources familiar with the matter.
The Mainichi said inspections are becoming more stringent at customs in Beijing and other locations as well, and that goods being affected include auto and consumer electronics components.
China became Japan's biggest trading partner last year and bilateral trade reached 12.6 trillion yen ($150 billion) in the January-June period, a jump of 34.5 percent over the same period last year, Japanese data shows.
The latest development comes when there is concern that Beijing is holding back shipments of rare earth minerals vital for electronics and auto parts, although China has denied that there is a ban on exports to Japan. (Reporting by Kiyoshi Takenaka; Editing by Edwina Gibbs)