China was Japan's biggest trading partner in the first six months this year, according to a report on Wednesday.
For the first time, Japan's exports to China surpassed those to the US.
The trade between Japan and the US dropped due to the global financial crisis, the Japan External Trade Organisation (JETRO) said in a report.
However, exports to China fell 25.3 per cent compared to last year's $46.5 billion and imports from the country dropped 17.8 per cent to $56.2 billion.
Trading with other countries and regions, including the US, showed larger declines, JETRO said.
In the January-June period, trade with China accounted for 20.4 per cent of the total trade volume of Japan, while that with the US accounted for 13.7 per cent and that with South Korea 6.1 per cent.
JETRO also projected a decline of China-Japan trade in 2009, the first yearly contraction since 1998 Asian financial crisis.