The bridge was built by the Japanese trading community in 1593 to link them with the Chinese quarter on the other side of a small stream. The bridge is obviously very solidly built, almost out of proportion to the small trickle which runs under it.
At either end of the bridge are alters to guardians of the bridge. One end has a pair of monkeys, while the other is guarded by dogs (left). There's also a sort of temple on the north side of the bridge, right in the middle over the stream.
http://asiaforvisitors.com/vietnam/central/hoian/bridge.html