The Sealed Library at Mogao

In the year 1900, in a stone corridor cut deep into a cliff, a man was sweeping away the dust.

His name was Wang Yuanlu, and his job was to look after the caves there. The desert wind blew all night, and every morning sand dulled the stone floor, so every morning it had to be swept. The story goes that at the end of the corridor, he rested a hand on a painted wall and tapped it lightly a few times, the way people tap something their hands already know well.

The sound that came back was not like the rest of the wall. It was hollow.

He tapped again. Still hollow. Behind that layer of painting was an empty space, and nobody in the area knew it was there.

To understand why that empty space mattered so much, we have to step far back, more than 1,500 years before that dusty morning.

In the northwest of China there is a town called Dunhuang, set in dry country where wind and sand blow all year round. Dunhuang never had rich fields, but it sat in exactly the right spot. It was a stop on the Silk Road, where caravans of merchants, horses and camels gathered before risking the crossing of the Taklamakan Desert. People rested here, traded goods, drank water, and prayed for a safe journey ahead. It is the kind of desert children in Vietnam have long pictured from the endless sandy roads of Journey to the West.

About 25 kilometers southeast of the town stands a sheer cliff, more than a kilometer long. Below it lies a dry riverbed with a row of poplar trees.

In the year 366, a wandering monk named Le Zun stopped right below that cliff as evening fell. The last sunlight of the day struck the rock, and for a moment he seemed to see thousands of golden Buddhas appearing on the cliff face. He stayed. He cut a small cave into the rock, just big enough to sit in.

Then others followed. Some cut caves to practice their faith. Others paid workers to cut a cave, then paid painters to cover its walls, as a good deed left for their children and grandchildren. The work did not stop after one lifetime, or even after 100 years. It went on from the 4th century to the 14th.

In the end, the whole cliff was hollowed out like a giant honeycomb. Today, 492 caves still keep their paintings and statues. Their walls carry about 45,000 square meters of paintings. Inside stand more than 2,400 painted statues. Some paintings show heavenly maidens flying with long silk ribbons. Others show camel caravans, or farmers bringing in the harvest. The whole site is called the Mogao Caves.

Now back to the sweeper and the wall that sounded hollow.

The plaster was taken down. Beneath it was a small doorway that had been sealed shut and then painted over, so skillfully that generation after generation walked past without noticing. Behind the doorway was a tiny room, only a few steps across each way. And in that room, piled from the floor almost to the ceiling, were books.

Tens of thousands of paper scrolls and books, along with paintings on silk, lay stacked in the dark. There was writing in Chinese, in Tibetan and in Sanskrit, and even in the scripts of peoples whose languages nobody speaks anymore. There were Buddhist sutras, Taoist books and Confucian books. There were also bills of sale, letters, and even the scrawled writing practice of some schoolboy long ago.

Those pages were written over about 700 years, from the 4th century to the 11th. Then, around the year 1000, someone packed them all into this small room, sealed the door, and painted over it. Why they did it, nobody yet knows for sure. All we know is that the room slept like that for about 900 years, until the morning the broom swept past.

Among that heap of paper was one long scroll, neatly rolled, its paper gone the color of tea.

That scroll is the Diamond Sutra, made in the year 868. The Diamond Sutra is a Buddhist text. What makes this copy special is that it was not written by hand. It was printed. A craftsman carved each character in reverse onto wooden blocks, brushed ink over the blocks, then pressed paper down onto them. Seven printed sheets were pasted together into a scroll about 5 meters long. At the very start of the scroll is a picture, also cut in wood, showing the Buddha seated and teaching in the middle of a crowd. To this day, it is the oldest complete, clearly dated printed book that the world knows of.

Yet that record is not what makes people remember this scroll. The reason lies in a few small words at the end.

There, the man who paid for the printing wrote his name, Wang Jie. He added that he had the sutra printed as a gift for all people, to be given away free to anyone who wanted it. And he wrote that he did it on behalf of his father and mother.

That is all. No rank, no title, not one word of boasting.

Almost 1,200 years ago, a son wanted to do something good for his parents. And what he chose to do was print a book and give it away. Not keep it. Not sell it. Give it.

In Vietnam, this part sounds very familiar. Older people in Vietnam still pool their money to print sutras and books, then leave a stack at the pagoda for anyone who needs one to take home and read. When it is done, they light a stick of incense and dedicate the merit to their father and mother. It turns out that on the edge of that faraway desert, a son did exactly the same thing. It is the same heart, set apart only by distance and by the years.

After 1900, the books from that small room did not stay together. They left the cave by many different roads, and today they lie scattered in libraries and museums in many countries around the world. The scroll of Wang Jie traveled far as well.

But the best part is happening right now. Since 1994, the libraries that hold those pages have worked together to photograph them, one sheet at a time. A few years later, they began putting the pictures online, for anyone who wants to look, free of charge. The research institute right in Dunhuang has also built its own image archive, with more than 60,000 sharp photographs. It brings together, in one place, pictures of pages that now lie half a world apart. In that archive, the scraps of paper sit side by side again, just as they did when they still shared one room.

The whole cave site has been photographed in the same way, one square meter of wall painting at a time. That way, if the colors fade someday, the photographs will still hold them exactly as they look today. In 1987, the Mogao Caves were added to the list of World Heritage sites.

So now, sitting at home, anyone can open that scroll and look at it, following all 5 meters of paper, from the picture of the Buddha at the start to the small line of writing at the end. That line still says exactly what it said from the beginning: printed as a gift for all people, on behalf of father and mother. Back then, Wang Jie only hoped that everyone could read it. That wish has come true at last. It just took a little while.