At the the multi-storey Karaoke Kan in the Shimbashi district of Tokyo, it doesn’t matter if you fail to hit the right notes during your rendition of Danny Boy or Never Gonna Give You Up. Likewise, there’s no need to reassure your friends when they murder a classic hit.

That’s because Karaoke Kan is one of a growing number of Japanese businesses catering to ohitorisama, or the solo customer. Inside your karaoke booth for one, no one can hear you scream.

More than a third of Japan’s 53m households are now occupied by a single person, according to the National Institute of Population and Social Security Research, with the proportion expected to rise to around 40% by 2040.

The rise of singledom has spawned its own industry – catering not just for the 18 million Japanese living alone, but also for married and cohabiting people who crave time away from their partners, workers who want to escape from colleagues during their lunch break and, yes, amateur crooners struggling with their falsetto.

All are united by the desire for temporary liberation from peer pressure that, according to some experts, has been exacerbated by the demands of social media.

“Our data shows sociable individuals tend to seek solo activities,” Motoko Matsushita, a senior consultant at the Nomura Research Institute, told Agence France–Presse.

There are 18m single households in Japan – just under a third of total households. Photograph: d3sign/Getty Images

The trend is being fuelled in part by changes in Japanese society created by the decline of the traditional family unit, in which two, and often three, generations lived under the same roof.

Government data shows the ratio of households with parents and children is gradually shrinking as fewer adults form long-term relationships. In 1980, just one in 50 Japanese men had never been married by their 50th birthday, and one in 22 women. Now that status applies to one in four men and one in seven women.

Few places in Tokyo encapsulate the solo lifestyle more than Ichiran, a chain of ramen restaurants where diners eat alone, largely uninterrupted by staff and out of sight of their fellow diners.

At the restaurant’s Shimbashi branch, interaction with other humans was kept to a minimum when the Guardian visited.

The first step was to buy a ticket for a portion of ramen from a vending machine. Then, a flashing blue light indicated a seat had become available at the far end of a counter divided into 10 booths by wooden partitions. A member of staff appeared, placed a bowl of steaming noodles on the table and lowered a slatted blind as he walked away. With just enough elbow room either side to manipulate the chopsticks, customers ate in near-isolation.

The ohitorisama phenomenon isn’t confined to dining out and singing karaoke. An array of businesses, from bowling alleys to travel agencies, now welcome solo customers in settings that traditionally cater to groups. They can reserve partitioned seats at cinemas and jump the queue for popular rides at theme parks.

“Businesses are offering various goods and services in response to the trend for people to enjoy activities alone,” Matsushita said. “The depth and range of these services is a reflection of the expanding nature of that trend.”

At Karaoke Kan, there was time for one last song before the hour-long session ended. The Guardian settled on the 1970s Eric Carmen hit – All by Myself – but soon realised that something wasn’t quite right; because for one precious hour on a freezing afternoon in a city of almost 14 million people, the song’s chorus, “don’t wanna be all by myself”, couldn’t have been further from the truth.