Sarah Takeda thought she had a good little business renting a traditional tatami-mat room in her house on Airbnb.
But she and other hosts in Japan are learning the hard way that the home-sharing site's fastest-growing market is also becoming the next flashpoint in a global battle over the sharing economy.
Hoteliers are up in arms, local residents complain that outsiders are invading their neighbourhoods, and Japanese officials say renting out private homes is illegal.
Calls for change have reached the highest levels of government, which is mulling a revision to the rules, as Japan's tourist numbers hit fresh records and Tokyo scrambles to build enough accommodation to host the 2020 Olympics.
But Takeda's hosting days are over, after local officials knocked on the door of her home in a quaint seaside town near the capital.
They quizzed her on minute details of the business, such as asking how she cleaned sheets for guest futons, Takeda said.
She was later threatened with a 30,000 yen ($280) fine or six months in jail if she kept renting.
"I had no idea Airbnb was against the law when I was running it," said Takeda, a pseudonym, who has since stopped renting the straw mat room for about 3,000 yen a night.
"They said some of the neighbours had commented that many foreigners were coming to our house."
Japan isn't alone. Fights over Airbnb have erupted in Spain, France, Germany and even in San Francisco, where the company is based, largely over rising real estate prices and noise complaints.
Still, Japan is particularly fertile territory for home sharing with visitor numbers soaring as a drop in the yen makes a once-notoriously expensive country a bit more affordable.
Last year, Japan drew some 19.7 million visitors, up 47 percent from a year earlier, straining hotel occupancy rates and highlighting Tokyo's accommodation problem.
Level playing field
The hotel industry, however, has been cool on the idea of unregulated players filling the gap.
"If ryokans (traditional inns) and hotels operate under the same regulations (as Airbnb hosts) and then we lose, I could accept it," said Satoru Haritani, chairman of the Japan Ryokan & Hotel Association.
"But if one industry is regulated and the other is not, and we have to compete under different rules, then that kind of situation would be nothing but unfair."
The health ministry, which oversees the hospitality sector, insists for-profit home sharing is still illegal under a nearly 70-year-old law—although enforcement can be patchy.
"Naturally, if there are signs of illegal activity...there could be penalties," said a ministry official who asked not to be named.
For its part, Airbnb said it tells hosts to check local laws, but pointed to a clash between the old and new economy.
"We often hear from many hosts that the current laws governing home sharing are unclear and difficult to understand. In fact, in some cases, they were written long before the internet even existed," it said in a written response to questions.
Clarity may come from above as the government mulls letting homeowners rent out their place for up to 180 days a year, and in exclusively residential areas, local media said.
The record numbers have created an untenable situation for bustling Tokyo, said Lauren, who rents out a pair of apartments at a family-owned building in a posh neighbourhood.
There are "lots of people who want to come to Japan", she said of the accommodation squeeze.
"Where should those people stay? What sort of standard should be put in place?"
Some hosts are not waiting on the legislature. Instead, they are taking matters into their own hands by suggesting travellers, such as 27-year-old Australian tourist Thomas Jurkiewicz, be creative with the truth.
There was a "little placard on the wall near the entrance that says if someone knocks on your door, do not say it's an Airbnb—say you are staying with your friend," Jurkiewicz said of a recent Tokyo rental.
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