The knife attack last week by a man on three first-grade boys near an elementary school in Nerima Ward, Tokyo, has once again raised the question of how to keep children safe.

In many communities in recent years, residents and convenience store employees have taken on the role of guardian. However, safety specialists point to the necessity of increasing the ability of children themselves to remain alert about strangers and protect themselves, as assaults can come at any time and are often difficult, if not impossible, for adults to prevent.

The 11 national convenience store chains that belong to the Japan Franchise Association have been performing what they call "Safety Station Activity" since 2005, organized by the police. According to an association official, around 47,000 convenience stores act as emergency shelters around the clock.