The credit crunch is a bursting ballon that had inflated to historic proportion over the last decade. The US (and some others like the UK) $1tn trade deficit (worth half of China's GDP) was paid for largely by foreign acquisition of US financial assets-backed paper. The credit boom economies ran deficits and the export-led growth economies collected foreign currency reserves.
Then this Summer China's growth reversed to become mainly explained by internal not external demand (falling trade surplus) and US growth mainly by external not internal demand (falling trade deficit). Now, yesterday, we learn that Japan has recorded its first outright trade deficit in 25 years!