Why are pu'er cakes sold in sevens? The qizi bing explained

Buy a standard pu'er cake and the wrapper will very often say 七子饼茶, qi zi bing cha. Buy a whole stack and you will get seven of them. The number is old, the name is fairly new, and the reasons given for both are a mix of record and trade lore.

What does qi zi bing cha mean?

Character by character: 七 (qī) seven, 子 (zǐ) sons or children, 饼 (bǐng) cake, 茶 (chá) tea. The usual English version is "seven sons cake tea".

The name describes the packing, not the tea. It says nothing about the leaf, the region, the year or whether the cake is raw or ripe. Any round cake that is packed seven to a stack can carry it, and the cake you hold is one of the seven "sons".

What is a tong?

A tong (筒, "tube") is the stack: seven cakes laid face to face and wrapped together. Some people call it a ti (提). The traditional wrap is dried bamboo shoot husk, the papery sheath that a growing bamboo shoot sheds, tied round with bamboo strips or wire. It is light and tough, it lets a little air through, and it has no strong smell of its own.

The numbers fit together neatly:

For where the 357 g figure comes from, see pu'er cake shapes and sizes.

Why seven, and not six or ten?

Three explanations are usually given. They do not exclude one another.

A Qing dynasty tax rule. Most accounts trace the number to a regulation of the Qing court, usually dated to the 1730s under the Yongzheng emperor, on tea traded out of Yunnan. As commonly quoted, it set seven round cakes to a tube, forty-nine liang to the tube, with tax and trading permits reckoned on that basis. If so, seven began as an official unit of account, and makers pressed and packed to match it. A liang of that period was a little under 40 g, so those cakes were lighter than a modern 357 g cake.

A convenient load. Yunnan tea left the mountains on mules and horses along the Tea Horse Road. A tong is a solid cylinder that one hand can lift, and tongs pack tightly into baskets that can be balanced on either side of a pack saddle. This explains why a fixed, modest unit was useful. It does not by itself explain why the unit was seven and not six or eight.

An auspicious number. The name is usually read through the phrase 多子多福, "many children, much good fortune". Seven sons stand for a large and prosperous family, and the round shape suggests reunion. This reading may well have been attached to a number that was already fixed for practical reasons. It is hard to show which came first.

When did the name come into use?

Later than the practice. For most of their history these cakes were simply called round tea, yuan cha (圆茶). The product name qi zi bing cha is usually dated to the 1970s, when Yunnan's state-run tea trade adopted it for cakes made by the state factories, largely for export. Accounts differ on the exact year and on whether the phrase had been in spoken use before.

So the seven is Qing or older, the 357 g weight is modern, and the name printed on the wrapper belongs to the state-factory era. The best-known recipe numbers such as 7542 come from the same period.

Are tongs still always seven cakes?

No. Seven 357 g cakes is still the default, but it is no longer the only format.

• Tongs of five cakes are common, especially for 200 g and 400 g cakes.
• Small cakes of 100 g or so are packed in various counts.
• Many cases now hold fewer than twelve tongs, so a "case" is not always 84 cakes.
• Paper or card tubes often replace bamboo husk. Some producers still use husk.

The tong label, or a line on the wrapper, normally states the cake weight and the number of cakes. Read it and do not assume. Our guide to reading a pu'er wrapper covers the other markings.

Does it matter to a buyer whether a tong is whole?

For drinking, no. A single cake from an opened tong is the same tea.

For keeping, a sealed original tong has two modest advantages. The husk shields the cakes from light, knocks and passing smells, and the seven cakes share one small environment, so they tend to age alike. Storage basics are in how to store pu'er cakes at home.