Late last month, three people were attacked inside the kimono shop they run in the mountain town of Kamiichimachi. The previous week an 82-year-old woman in Hyogo, central Japan, was targeted as she hung out her washing.
The government is sufficiently worried to have announced an emergency investigation into the problem, although the culprits are unlikely to pay any heed to the authorities. They are, after all, only following their instincts.
This year has been the worst in living memory for attacks by tsukinowaguma, Japan's indigenous black bear, with one man killed, more than 80 people injured in the past six months and in excess of 2000 reported sightings of bears countrywide.
"We are in discussions with bear specialists and while there are many suggestions at this stage for why we are seeing so many more incidents this year, the study has not yet reached any conclusions," said Akinori Ogawa, a spokesman for the environment ministry.
Early indications, however, are that this year's problem is the culmination of several factors, both one-off events and longer-term concerns, he said.
"The crops of fruit and nuts in the mountains have been particularly bad this year and that, we believe, is a result of the unusual weather we have had," he said.
"A more fundamental problem is that the bears' living environment is being degraded by development and human activities, changes which have been going on for many years"
Akinori Ogawa, spokesman for Japans' environment ministry
"The summer was exceptionally hot and we have had more typhoons this autumn."
Acorns, a staple for black bears stocking up for the long winter months of hibernation, have been smaller than usual, while other crops have been hit by torrential rain and high winds.
"A more fundamental problem is that the bears' living environment is being degraded by development and human activities, changes which have been going on for many years," Ogawa said. "It is just unfortunate that we are seeing a combination of all these conditions."
The result is that bears that are naturally shy and avoid contact with humans are taking their chances in farmers' fields and the rubbish bins of suburban homes.
Inevitably, more bears are coming face-to-face with humans, most of whom have little idea how to react when confronted by creatures that can grow up to 1.5m tall and weigh on average 100kg.
Bears - some with cubs in tow - have wandered into people's homes, fire stations and kindergartens, although there has so far been only one death, of a farmer whose dog disturbed a mother bear with two cubs in a corn field.
"If there's one thing you should never do, it's mess with a mother bear that is looking after her young," says C W Nicol, a Welsh-born environmentalist and author who lives in nearby Shinanomachi, in the northern prefecture of Nagano.
Media reports of the problem
have been criticised as hysterical
"We'll have snow here by the end of November and all they are doing is eating as much as they can before they need to go into hibernation," said Nicol, who was a game warden in Africa and an environmental adviser to the Canadian government before moving to Japan.
For the past 20 years he has studied the confrontation between bears and humans and believes steps need to be taken to make it less attractive for bears to come down from the mountains for their food.
"Some orchards have been ringed with electric fences this year, and that has proved effective, but it just means the bears go into people's back gardens instead," he said.
"We have got to stop making rubbish available to them, like they do in North America. We have to train people to deal with our wildlife," he added. "But most importantly we need to replace the spindly coniferous forest that has been planted with the mixed woodland that is their natural habitat."
Coniferous forests were planted after the second world war in a campaign to make Japan self-sufficient in lumber. That was never achieved as companies switched to cheaper, imported wood, so the forests came to be ignored.
He also criticised media coverage of the problem as "hysterical", although the Japanese public appears to have taken the bears' plight to heart.
Lending a paw
Three days after an appeal for donations of acorns that would be taken deep into the bears' habitats, the Japan Bear and Forest Association has stopped answering its telephones and left an answering machine message pleading for no more acorns to be sent.
The group, based in Hyogo Prefecture, received 200 boxes, envelopes and parcels containing acorns in two days and its phone lines were overwhelmed with queries and offers of assistance.
"The number of bears will fall rapidly if we keep killing them whenever we see them"
Mariko Moriyama, Japan Bear and Forest Association chairman
The group has managed to deposit 700kg of acorns in the mountains of the prefecture and is appealing for volunteers to help with the meal delivery service.
It is also appealing for officials in rural towns not to simply shoot any bears that wander into rural villages or towns.
"The number of bears will fall rapidly if we keep killing them whenever we see them," Mariko Moriyama, chairman of the association told the Yomiuri newspaper.
Instead, she said, residents of areas that are also home to bears need to be shown how to co-exist with the natural world and take steps to make their homes and gardens less attractive to bears, such as not leaving rubbish in places where they can get it.
Temperatures are dropping in the mountains of northern and central Japan and the bears are scavenging for their last meals before going into hibernation.
There are fears that these last few autumn weeks may be the most dangerous of all for the human residents of those same areas.