If you are an old China hand, you will already love dumplings, or jiaozi. And if you are new to the country, it will be sooner rather than later when you encounter a dumpling, or more likely an entire platter of dumplings.

Jiaozi are eaten all year round, during important festivals, and especially during the winter solstice.

As a southerner, I regarded the jiaozi as a snack, a sort of stocking filler during dim sum sessions. And then I married into an old Beijing family.

The first time I had northern-style dumplings was at the welcome meal at my mother-in-law's hutong courtyard house. Two sister-in-law were hard at work deftly rolling out the handmade skins and putting the filling into each. The finished dumplings were neatly laid out on large round reed trays.

When it was time to cook them, one turned to me and said, "Sister, how many can you eat?"

Eyeing the large dumplings on the tray, I hesitated and said six. They burst into laughter. Well, it seems everyone eats at least 20.

All these decades later, I still cannot finish more than 10 at a go, unless they are fried as pot-stickers.

My husband later explained the thick wrappings and fillings to me.

Northern dumplings are large and doughy because they are designed to satisfy hunger. They are regarded as a staple. There is more vegetable than meat in them, and the most common filling is probably chopped napa cabbage and pork.

Another characteristic is the use of strongly flavored herbs such as fennel tops and chives, aromatics that the Western palate may consider too strong as vegetables.

Chopped fennel tops and a bit of pork is a classic Beijing dumpling filling, as are chives and scrambled eggs, lamb and carrot, beef and onions.

Unlike in southern China, seafood is seldom used here.

Still, these hefty dumplings are the originals, and the dainty versions in the south with their light wrappers bursting with seafood and meat evolved from jiaozi brought south by merchants from the north plying the maritime trade routes.

Dumplings are eaten during almost every major festival, but it all began with one man and the winter solstice.

The man was Zhang Zhongjing, a doctor who lived during the Eastern Han Dynasty (25-220). He was most famous for his dissertations on Shanghan Lun, a medical text that sets out the basic principles of traditional Chinese medicine. Many physicians still see his tome as their medical Bible.

Besides being a learned TCM practitioner, he was also a great philanthropist.

He had been ready to retire after a long stint at court and had gone home to what is now Henan province. It was bitterly cold and near the winter solstice and there were plenty of hungry, sick people on the streets, all with frostbite on their ears.

The good doctor was very upset by the sight, and he and his disciples quickly set up a stall by the roadside.

Here, he dispensed medicine and advice, along with a huge cauldron of mutton soup. He also created ear-shaped dumplings with a generous crust and a meat filling. He served everyone who came two dumplings and a bowl of piping hot broth.

It wasn't too long before their frostbite and chilblains were cured. The rich mutton broth assuaged their hunger and warmed their bodies.

Zhang was simply following the principles of traditional Chinese medicine, which dictates that winter is a time to replenish the body while it rests, according to the ancient timetables of when and how to eat.

Animals hibernate, and man is forced to rest in winter while the ground is frozen and lying fallow. That is why this is the best season to eat well, because the energy is stored and not lost immediately in manual labor.

The recipe that Zhang used for his mutton soup is lost to time, but we can be assured that it would have had plenty of beneficial herbs. In many parts of China, to this day, a popular winter soup is mutton cooked with Chinese yam, shanyao, as well as angelica root and goji berries.

Because of Zhang, too, dumplings became a tradition for the winter solstice. They are such a popular food that they are now eaten on birthdays and for funerals, weddings, farewells and welcome meals.

The winter solstice is both a beginning and an end. On this longest night of the year, the bitter winter draws to an end. After this, the days start getting longer and warmer and the countdown to spring begins.