Originally Posted by rkkwan
HKG-SHA/PVG are important business routes, and fares are often higher than other flights to China.
Fares to HKG are higher because it's considered an international (well, "regional" is the preferred term) destination.
Taiwan has ALWAYS been an expensive destination from mainland China. The cheapest way for foreign travelers to hit both Taiwan and PEK/PVG on the same trip is to use an open jaw so you only need to connect the dots in one direction (which can be accomplished as little as $200 with a little luck and flexible scheduling).