Far out in the Eastern Sea, the old geographies say, lie three islands — Penglai, Fangzhang and Yingzhou — where the immortals live.
The islands are built of gold, silver and crystal; their palaces are white jade; the birds and beasts there are all pure white; and on them grow the herbs of deathlessness. Sailors have seen them from far off, shining on the horizon like clouds with foundations. But the islands are never where they were. They drift. Worse, they drift away: the histories say that whenever an expedition approaches, a wind rises and carries the ships off course, or the islands simply sink beneath the water and surface somewhere else.
This did not stop emperors. The First Emperor of Qin sent the court magician Xu Fu east with thousands of young men and women to find Penglai and bring back the elixir; Xu Fu never returned, and legend made him the founder of Japan. The Emperor Wu of Han spent a fortune on the same quest. Penglai became, in effect, the official mirage of Chinese power — the thing every ruler wanted and none could have, because the only passport to the isles is the one thing an emperor cannot command: having become immortal yourself.
In the story-library, Penglai is the eastern pole of the sacred map, paired with Kunlun in the west. But their temperaments differ. Kunlun is a court — the Queen Mother’s, with rules and ranks. Penglai is a hermitage — immortals at ease, beyond administration, playing chess as centuries pass. When a character in a tale vanishes at the end ‘eastward, toward the isles’, it means they have left not just the world but its paperwork.