Chihiro Nishijima's cellphone rang one evening last May when she was away from Tokyo on a business trip.
It was from the day care center in Tokyo where her 1-year-old son was. They told her he had developed a fever and they needed her to come and pick him up.
Nishijima asked one of her friends to take care of him as well as her 6-year-old daughter until 10 p.m., as her husband was also away on a business trip.