The excerpt explains how dark forest deterrence first depended on more than three thousand oil-film-wrapped nuclear bombs around the sun. If detonated, they would make the sun flicker and broadcast Trisolaris's position, but the system was unstable and relied on primitive electromagnetic radiation. After the droplets stopped blocking the sun, humanity added a solar superantenna broadcast system.

Humanity then demanded gravitational wave and neutrino transmission technologies from Trisolaris because these methods had far longer reach than electromagnetic waves. Neutrinos required directional beams, while gravitational waves were omnidirectional, so gravitational wave broadcasting became the main basis of deterrence. The transmitters used vibrating strings of degenerate matter, which decayed over time and had to be renewed roughly every half century.

Early planners wanted many broadcasting stations, but the equipment could not be miniaturized and was extremely expensive. Only twenty-three stations were built. In Deterrence Era Year 6, the human-supremacist Sons of the Earth nearly seized an Antarctic gravitational wave station, using infiltrators and advanced weapons; defenders prevented disaster by destroying the antenna.

The attack frightened both Earth and Trisolaris, leading to strict control of gravitational wave technology. Under Trisolaran pressure, the twenty-three stations were reduced to four: three buried terrestrial stations in Asia, North America, and Europe, and one aboard Gravity. These transmitters used active triggers rather than Luo Ji's older dead hand system, because another person could take over if the Swordholder died.

The excerpt then turns to the unresolved threat of the droplets. Trisolaris was permitted to keep four droplets beyond the Kuiper Belt under human monitoring, though two later followed Gravity to pursue Blue Space. Six other droplets supposedly left the Solar System, but humanity suspected that Trisolaris, having learned deception from humans, had hidden them nearby. Because a droplet could cross the reliable detection zone around Earth in ten minutes, that interval became the Swordholder's entire window to decide whether to activate deterrence.