In the 1990s, cai li prices rose to several thousand yuan (about $200 to $400 at today’s conversion rates), mirroring the country’s growing prosperity. But it was only starting in 2002-03 that villagers noticed a sharp spike in cai li prices, which shot up to between 6,000 to 10,000 yuan — several years’ worth of farming income.

Not coincidentally, this was also the period when the first generation of children since the family-planning policy was launched in 1979 started reaching marriageable age…

Matrimony was catching. Two neighbors sought Ms. Cai out, and asked her to act as matchmaker for their sons. Ms. Cai recommended two girls within a few days. The neighbors each paid 40,000 yuan in cai li.

On Jan. 28, all these brides vanished, leaving the villagers reeling.