Japan launched a nationwide probe on Friday into thousands of mysterious, sharp-edged pieces of metal in different sizes found jutting out of roadside guardrails across the country.
Japanese media have been debating whether the metal shards were planted by pranksters linked by the internet or if they could all have been formed by car fragments in crashes.
At least several people have been injured while cycling or walking beside the guardrails. The metal pieces, sticking out either through holes or attached artificially, are usually triangular and range in length from 10cm to 60cm.
“We will make an urgent inquiry into the matter to see whether they have been attached intentionally or due to other causes,” Chief Cabinet Secretary Hiroyuki Hosoda told a regular news conference.
The top government spokesperson added: “A considerable number of people, including pedestrians and cyclists, have been injured and we call on people to be fully aware.”
The National Police Agency said it has yet to compile statistics on the mystery objects.
But Japanese media, contacting officials at the country’s 47 prefectures, said as many as 7 400 pieces of protruding metal have been found on road guardrails since the mystery surfaced last week.
The Tokyo Metropolitan Police Department said it has confirmed at least 10 cases.
“It is not yet clear how they have been formed, although some of them may have resulted from car crashes,” a spokesperson said.
Since the guardrail mystery emerged, new cases have come to light of people injured earlier.
In August 2003, a 17-year-old boy was injured when his left leg was caught by a shard while riding a bicycle in Toyokawa near the central city of Nagoya, press reports said. The injury required four weeks of treatment.
A 16-year-old boy had to have seven stitches for a similar cut in his left thigh last December in Chiba, a satellite city south-east of Tokyo. — AFP