Twice in Vietnamese history, the tide at the mouth of the Bạch Đằng river decided the fate of the country. In 938, Ngô Quyền defeated a Southern Han fleet by planting iron-tipped stakes in the riverbed, hidden at high tide, then luring the enemy ships upstream and waiting for the water to fall. In 1288, during the third Mongol invasion of Đại Việt, the general Trần Hưng Đạo used the same trick against the fleet of Kublai Khan's Yuan dynasty, trapping and destroying it. In the fields around Quảng Yên, archaeologists have found rows of those ancient wooden stakes, still standing in the mud, and the Yên Giang stake yard is one of the sites where you can see them preserved.
The area is part of a landscape shaped by water: rice paddies, fishponds, mangroves and the wide estuary where several rivers meet the Gulf of Tonkin. A short ride east lies Hạ Long Bay, with its thousands of limestone islands rising from the sea, and the industrial port city of Haiphong is just across the river to the south. Inland, near Uông Bí, Yên Tử mountain was the retreat of the Trần king Trần Nhân Tông, who abdicated to become a monk and founded the Trúc Lâm school of Zen; pilgrims still climb to its pagodas.
Riding here means dealing with Vietnamese traffic: a dense stream of scooters, trucks and buses, with lots of horn and little lane discipline. Motorcycles are banned from the expressways, so you will use the national and provincial roads, which are busy but usually well surfaced. The countryside roads along the dykes and between the paddies are quieter, though narrow, with buffalo, bicycles and children on their way to school. The weather is hot and humid in summer, with typhoons possible from July to October; winter can be cool, damp and misty.
Uông Bí, eleven kilometres away, and Haiphong have plenty of fuel, food and accommodation, and every village has small petrol stations and noodle shops. Try bánh đa cua, a crab noodle soup from Haiphong, or fresh seafood in Quảng Yên. Bring a good rain jacket, keep your wits about you and enjoy the chaos.