“But in this dark forest, there’s a stupid child called humanity, who has built a bonfire and is standing beside it shouting, ‘Here I am! Here I am!’” Luo Ji said.

“Has anyone heard it?”

“That’s guaranteed. But those shouts alone can’t be used to determine the child’s location. Humanity has not yet transmitted information about the exact position of Earth and the Solar System into the universe. From the information that has been sent out, all that can be learned is the distance between Earth and Trisolaris, and their general heading in the Milky Way. The precise location of the two worlds is still a mystery. Since we’re located in the wilderness of the periphery of the galaxy, we’re a little safer.”

“So what’s the deal with the spell?”

“Using the sun, I transmitted three images to the cosmos. Each one consisted of thirty points representing the planar projection of a three-dimensional coordinate system containing the position of thirty stars. Combining the three images into three-dimensional coordinates forms a cubic space populated by those thirty points. That represents the relative positions of 187J3X1 and its twenty-nine surrounding stars. There’s also a label pointing out 187J3X1.

“Think about it carefully and you’ll get it. A hunter in a dark forest, stalking with bated breath, suddenly notices that a piece of bark has been stripped from a tree in front of him. On the eye-catching bit of white wood that’s been revealed is a position in the forest, written in characters all hunters can recognize. What will he think about that location? He’s certainly not going to imagine that someone has laid out supplies for him there. Out of all the possibilities, the most likely one is that the blaze is informing everyone that there’s live prey at that location that needs to be eliminated. It doesn’t matter what motivated someone to leave the mark. What’s important is that the dead hand has stretched the nerves of the dark forest to the breaking point, and it’s the most sensitive nerve that’s most liable to make a move. Suppose there are a million hunters in the forest—the number of civilizations on the billions upon billions of stars in the Milky Way could be thousands of times that. Perhaps nine hundred thousand of them will disregard the marking. Of the remaining one hundred thousand, maybe ninety thousand of them will probe the location, and, after confirming that it has no life, disregard it. But one of the remaining ten thousand hunters will surely make a choice to fire on that position, because for civilizations at a certain level of technological development, attacking may be safer and less of a hassle than probing. If there’s really nothing at that location, then it’s no loss.

“Now,” Luo Ji concluded, “that hunter has appeared.”

“That spell of yours can’t be sent anymore, right?”