On holiday in Hanoi, I found myself trying to explain "comfort women" to my 13-year-old son. The historic settlement on Dec. 28 between Japan and South Korea had lit up everyone's phones, and he wanted to keep up with this breaking news.

Hearing the phrase "comfort women," he may have thought of his mom or of his two sisters, who were both home from college for a few weeks. But the image on our phones featured two dark-haired, dark-suited men shaking hands, a South Korean flag to the left, a Japanese flag to the right. Not many women or much comfort in the photo.

"So what's 'comfort women'?" he asks.