Early morning sees Hoan Kiem Lake at its best, stirring to life as walkers, joggers and tai chi enthusiasts limber up in the half-light. Space is at a premium in this crowded city, and the lake’s strip of park meets multiple needs, at its busiest when lunch-hour hawkers are out in force, and easing down slowly to evenings of old men playing chess and couples seeking twilight privacy on benches half-hidden among the willows. The lake itself is small – you can walk round it in thirty minutes – and not particularly spectacular, but to Hanoians this is the soul of their city.

The name of the lake, which means “Lake of the Restored Sword”, refers to a legend of the great Vietnamese hero, Le Loi, who led a successful uprising against the Chinese in the fifteenth century. Tradition has it that Le Loi netted a gleaming sword while out fishing in a sampan and when he returned as King Ly Thai To, after ten years of battle, he wanted to thank the spirit of the lake. As he prepared the sacrifice there was a timely peal of thunder and the miraculous sword flew out of its scabbard, into the mouth of a golden turtle (Vietnamese use the same word for turtle and tortoise) sent by the gods to reclaim the weapon.

A good way to get your bearings in Hanoi is to make a quick circuit of the lake, a pleasant walk at any time of year and stunning when the flame trees flower in June and July. The sights below are given in a clockwise order, beginning at the iconic Huc Bridge (possibly the most photographed sight in the city) at the lake’s northeast corner.

Den Ngoc Son

Crossing over the striking The Huc Bridge, an arch of red-lacquered wood poetically labelled the “place where morning sunlight rests”, you find the secluded Den Ngoc Son, “Temple of the Jade Mound”, sheltering among ancient trees. This small temple was founded in the fourteenth century and is dedicated to an eclectic group: national hero General Tran Hung Dao, who defeated the Mongols in 1288, sits on the principal altar; Van Xuong, God of Literature; physician La To; and a martial arts practitioner, Quan Vu. The temple buildings date from the 1800s and are typical of the Nguyen Dynasty; in the antechamber, look out for the dragon heads, carved with bulbous noses and teeth bared in manic grins.

Statue of King Ly Thai To

Heading south along the eastern side of the lake, you’ll come to an imperious statue of Hanoi’s founding father, King Ly Thai To, which was erected in 2004 in anticipation of celebrations to mark the city’s millennium in 2010. At dusk, the expanse of polished stone paving around it provides an incongruous venue for Hanoi’s small but keen band of break-dancers.

The Tortoise Tower

A squat, three-tiered pavilion known as Thap Rua, or the Tortoise Tower, ornaments a tiny island at the southern end of Ho Hoan Kiem. It’s illuminated after dark, and is another of Hanoi’s most prevalent icons, with its reflection shimmering in the lake. It was built in the 19th century to commemorate the legend of the golden turtle and the restored sword, but is not accessible to the public.

The General Post Office

At the southeast corner of the lake stands the enormous General Post Office, which marks the northern fringe of the French Quarter. Opposite the post office, on the shore of the lake, stands a small and ancient brick tower. This is all that remains of an enormous pagoda complex, Chua Bao An, after French town planners cleared the site in 1892 to construct the administrative offices and residences of their new possession.

St Joseph’s Cathedral

As you round the southern tip of the lake and head up its western shore you’ll spot Hanoi’s neo-Gothic cathedral over the rooftops to your left. Veer left along Hang Trong, then left into Nha Tho, to reach it. It was constructed in the early 1880s, partly financed by two lotteries, and though the exterior is badly weathered its high-vaulted interior is still imposing. Among the first things you notice inside are the ornate altar screen and the stained-glass windows, most of which are French originals. Over the black marble tomb of a former cardinal of Vietnam stands one of several statues commemorating martyred Vietnamese saints, in this case André Dung Lac who was executed in 1839 on the orders of the fervently anti-Christian emperor Minh Mang.

The cathedral’s main door is open during services (the celebration of Mass was allowed to resume on Christmas Eve 1990 after a long hiatus); at other times walk round to the small door in the southwest corner. The cathedral is on Nha Tho, one of the most fashionable streets in the city for shopping, dining and drinking.

Ly Quoc Su Pagoda

Walking north from St Joseph’s Cathedral along Ly Quoc Su brings you to Ly Quoc Su Pagoda, a small pagoda with a genuinely interesting collection of statues. Ly Quoc Su (sometimes also known as Minh Khong) was a Buddhist teacher, healer and royal adviser who cured the hallucinating King Ly Than Tong of believing he was a tiger. Quoc Su’s image resides alongside that of the white-bearded Tu Dao Hanh on the principal altar of this twelfth-century temple – when it later became a pagoda they simply added a few Buddhas behind. In front of the altar, two groups of statues face each other across the prayer floor: four secular, female figures sit opposite three perfectly inscrutable mandarins of the nineteenth century, clothed in rich red lacquer.

From Ly Quoc Su, make your way back to Hoan Kiem Lake and continue northwards to where Thuy Ta café offers respite from the traffic and a fine place to relax.