An excellent question! Based on the experience of the Chinese "mini-crash" of Feb/March 2007, the carry trades would unwind.
So the USD would fall against the JPY and maybe also the CHF, but go up against everything else.
I would short AUD/JPY as first choice in such a case, as AUD is a carry currency and a commodity currency, both of which would be hit by a Chinese bubble popping.
Maybe short NZD/USD and GBP/JPY too.
I like to keep some carry pairs spare for some counter-trend scalping during these unwinds...CAD/JPY for example.
JMHO....
