Climb out of Hà Giang on the QL4C and the first big reward comes at around 1,500 metres, at Quản Bạ, where the road crests a pass known as Heaven's Gate and the karst country of the far north opens in front of you. From the viewpoint you look down onto Tam Sơn, the district town, in a broad valley of rice and corn fields, and beyond it two small, perfectly rounded hills sit side by side. The locals call them the Fairy Bosom, and once you have seen them, you will not need it explained.
The legend goes that a fairy came down from heaven and fell in love with a local H'Mông boy, and when she was called back to the sky, she left her breasts behind to feed their child. The story is told with a wink, but the hills are a genuine sight, especially in the morning when mist lies in the valley and the sun catches their tops. Tam Sơn itself is a small, busy market town, the first real stop after Hà Giang, with a few homestays, guesthouses, cafes and noodle shops.
The landscape changes here. Up to now the road has followed rivers and valleys; from Quản Bạ onwards you are on the edge of the Đồng Văn Karst Plateau, a huge area of limestone peaks, deep valleys and rocky fields where farmers grow corn between the stones. The people are mostly H'Mông, Tày, Dao and other ethnic minorities, and you will see women in embroidered skirts and children walking home from school along the road. The area is poor, and life is hard, but people are friendly and often curious about passing riders.
The riding is spectacular but demanding. The QL4C is a narrow mountain road with endless hairpins, steep gradients and sheer drops, and the surface varies from good tarmac to potholes and gravel. Trucks, buses and local motorbikes share the road, and some drive fast and in the middle. In the rainy season, from May to September, landslides can block the road, and fog can reduce visibility to a few metres. The best time to ride is from October to April, when the skies are clearer and the buckwheat flowers bloom pink and white in late autumn.
Fuel is available in Tam Sơn and in Yên Minh, the next town, but stations can be few and far between beyond, so keep your tank topped up. Try the local corn wine, but only at the end of the day.