The brick.
Loose tea does not survive a four-thousand-metre walk; compressed tea does. The caravans carried the leaf pressed into bricks and discs — steamed, packed into cloth bags and pressed until it was dense as furniture — because compression was preservation, and a mule could carry more value per load. The pressing houses of the tea villages were, functionally, the road's first factory floor, and the cakes in Jingmai's courtyards today are pressed the same way.
The mule train.
The gradient decided everything else. From the tea mountains at 1,400 metres to the Tibetan plateau at 4,000, the road climbs through gorges that turn back the weather, and the animal that could do it was the mule — sure-footed, cheap to feed, and bad-tempered in exactly the way a mountain road requires. A train ran thirty to a hundred head, with the lead mule's bell setting the rhythm and the head horseman's word as law. The stone stairs they wore into the mountainsides are still there, and still the fastest line up some slopes.
The way-station.
Every two or three days' walk, the road needed a town with water, feed, beds and a market: the way-station. The best survive — Weishan, Jianchuan, and above all Shaxi's Sideng square, where the gate towers, the inn courtyards and the cobbled market were all built to the same specification: hold a hundred mules, feed their men, and move the trade on. The Friday market that still assembles there is the same machine, idling at low revs.
The ledger.
The trade ran on credit, not cash. A tea house in Menghai supplied a caravan master; the caravan master delivered to Lhasa months later; the horses and the wool came back down the same path. Every way-station kept ledgers, and the great families' fortunes were records of who owed whom across a season's walking. The road's romance is real — but it was romance financed by paper, and the towns that endure are the ones where the paper kept flowing.
Keep reading
Shaxi's Friday market
Pressing the cake
Tea with meals