Island of the Sea Women by Lisa See
After the Japanese occupation ends, the inhabitants of the island soon discover that the arrival of an American occupying force makes matters worse. They must cope through more and death and loss and the splitting of the country into parts and factions. Struggles between pro-communists, anti-communists and rebels decimate the male population, cause the deaths of many innocent men, women and children, and bring the islanders near chaos and starvation.
Following the bloodshed, the survivors are poisoned by guilt and self-blame. They succumb to the dangers of the gossip mill, and live in constant fear because those who lost relatives, innocent or not, are tainted by the old custom of guilt by association. As they are watched, harassed, gossiped about, threatened and forbidden to leave the island, some turn on themselves and each other.
On top of this, the Haenyeo, who had followed an ancient and isolated matriarchal culture centered around diving for food, goddess worship and shamanism are being catapulted into the future. In a few short years they must adapt to the disappearance of their old life and values and cope with huge and sudden changes, as outsiders legislate their old female diving collectives out of existence and transform their island into a tourist destination. But it is impossible to paper over past tragedy by constructing temples to consumer culture on top of it.
The volcanic island of Jeju (or Cheju) is now a UNESCO Heritage site, but a great deal of dark history took place there during and after WWII and the division of Korea into north and south. In 2012, the Washington Post carried a story about the island; at the time, the government was planning to build a naval base on it, and the islanders were protesting against this.