Hoping to minimize the negative effects that smartphones can have on children, students in elementary and junior high schools in Kariya, Aichi Prefecture, will be banned from using cellphones after 9 p.m.

The ban, however, will have no binding power and it won’t be officially issued by City Hall. Whether to follow the rule will be left to each family.

The PTA and a local group consisting of teachers, social workers and police came up with the idea several months ago and agreed last month that they will work together to “request” that parents and children follow the rule starting in April, said Fushitoshi Ohashi, who heads the group and is the principal of Karigane Junior High School.

With the spread of smartphones, an increasing number of kids use their handsets until late at night to communicate with friends, and this could cause problems, Ohashi said.

For instance, the popular messaging application Line allows users to check if messages have been read. Thus, some students feel obligated to reply, and this leads to a continuous back-and-forth that can stretch on deep into the night, he said.

“They feel they have to reply because their friends will ask why they aren’t responding if they don’t,” Ohashi said. “When this happens, they can’t study even if they want to because they are preoccupied with communicating . . . it’s hard to just ignore (messages).”

He added that not replying can sometimes damage friendships.

After the new rule is put in place, “they can tell their friends that they couldn’t reply because it was after 9 p.m. We will start this (rule) to give children a reason (to get away from cellphones),” he said.

According to Ohashi, some parents have said the rule will make it easier for them to tell their children to stop playing games on their phones, which can last late into the night.

After 9 p.m., the kids will have to give the phones to their parents to refrain from using them.

Since the rule will have no binding power, there will be no punishment for students who don’t follow it, Ohashi said.

Kariya has about 13,000 elementary and junior high school students. Ohashi said a survey conducted in November showed that 58.2 percent of junior high school students have cellphones.