Two hundred and sixty-two years ago, the feudal domain of Hachinohe was besieged by wild boars. The Wild Boar Famine that resulted, writes environmental historian Brett Walker in his recent book "Toxic Archipelago," was the result of "the perfect ecological storm."
That came about because farmers in the domain along the southeastern coast of what is now Aomori Prefecture had recently begun growing soybeans to sell in the shogunate's capital of Edo (present-day Tokyo).
To cultivate their new cash crop, they would slash and burn fields, then plant and harvest beans from them until yields fell and they moved on to newer fields. In doing this they unintentionally left behind ideal feeding grounds for boars, which dug up tubers in the abandoned plots and rootled the tilled land for worms and grubs.