Rintaro Kikuchi has a simple explanation for why nearly half of the adults in Japan are now celibate and the country’s birth rate is plummeting.

“The apartments that young, single people have to rent in Tokyo are cramped and have little natural light, so they are dark and depressing”, he told the Telegraph.

“The bathrooms are only just large enough for one person and kitchens are so small you can’t really cook.

“There is no happiness in these homes, where you would be embarrassed to invite someone in”, he said.

Mr Kikuchi’s goal, then, is to turn Japan’s poky flats into airy, comfortable spaces where passion can flourish, complete with stripper poles and baths in the middle of the living space.

To date, he has completed ten projects, including a complex of six flats with a communal roof garden designed to allow residents to mingle.

“I got married quite early, at 23, but as the years went by a lot of my friends were not able to find a partner”, he said. “I feel that a happy marriage, with a loving wife or husband and children, makes us complete and content in our lives”.

One day, Mr Kikuchi visited a friend who had endured a series of relationships that each only lasted a few months. He was horrified at her apartment, in the swish Sendagaya district of Tokyo.

“No sunlight could find its way in, it felt cold and the kitchen and bathroom were tiny”, he said. “She felt sad living there and I wanted to leave again as soon as I had set foot inside the front door”.

At just 430 square feet - a fairly common size for many urban apartments in Japan - she set him a challenge of turning the hemmed-in home into a love palace.

The internal walls came out, the kitchen was enlarged and modernised, the bathroom received a similar makeover and the artificial flooring was replaced with real wood. After a few personal touches were added, Mr Kikuchi’s friend threw a house-warming party. Six months later, she had a boyfriend and she is now married.

“We have to have happiness in our lives”, said Mr Kikuchi. “If we have a comfortable and welcoming home, we feel better in ourselves, in our jobs and in our relationships. And that makes us more attractive and it is easier to find a partner”.

To raise the temperature further, a traditional square wooden bath has been installed on the roof that offers a spectacular view of sunsets and the night sky.

Another of his recently completed projects is designed more with a woman tenant in mind and has a large bath that looks out through the balcony doors, the shower is large enough for two to share and the kitchen enables a couple to cook in unison.

And, in the middle of the living room, is a stripper pole.

“I prefer to think of it as a form of exercise, like yoga, and you have to be very strong to do pole dancing well”, Mr Kikuchi said. “It builds muscles and there has been a boom in pole dancing classes here in recent years.”

But he conceded that a provocative pole dance might go some way to a couple taking their relationship to the next stage.