By Chris Hogg
BBC News, Tokyo
A Japanese businessman has been acquitted of raping and killing British bar hostess Lucie Blackman in 2000. But he was convicted of killing an Australian hostess, Carita Ridgway. Carita and Lucie were among thousands of foreign women who have been lured to work in one of Japan's hostess clubs.
A hostess entertains a Tokyo businessman
A woman working as a hostess in a Japanese bar has to concentrate on just one task, keeping the customer happy.
Happy customers stay longer. They drink more of the bars' expensive drinks.
That means more commissions for the hostess and more profits for the bar.
There are thousands of hostess bars in Tokyo. Club Lounge Monina is one of the more respectable establishments.
Paid to entertain
The foreign women working there told me they were not prostitutes but entertainers - but they were not keen to give their real names for fear of what their friends and families back home might think of them.
'Karen', who is from the Philippines, said: "Our job is just to talk to people who come in to drink, to sing along with them on the karaoke machine, to make them laugh and to try to listen to them."
Lucie Blackman was killed while working as a hostess
She works five nights a week from Monday to Friday at the club. She says she earns 2,500 yen (£10) an hour.
But that is just the beginning. Hostess bars have complicated systems of rewards and bonuses.
"We get tips as well as the commissions for the drinks and if we invite customers to the bar we get money for that too," said Karen.
Hostesses can also go on dinner dates with customers, known as dohan. They get their dinner paid for and then bring the customer to the club.
The night we were at Club Lounge Monina one of the customers was giving out gifts to a couple of the women he was sitting with.
The women who work there insisted they did not offer any sexual services to the customers.
'Vivienne', who is from Brazil, said she was worried before she started but she said: "I was so tired of working in a convenience store. I thought to myself, I will give it a try. That was two-and-a-half years ago. I'm still here, I think it is OK.
"Maybe some girls work as prostitutes, I don't know what goes on in other places, but not here."
The bar we visited is owned and run by Monina.
At 34, she is unusually young to be a hostess boss or mama-san.
"The best hostesses are good looking for sure, but then it also depends on how they attract customers. It's not easy if you're not smart," she said.
Currently most of the women she employs are from Asia.
"I used to have many girls, from Cameroon, Senegal, Europeans, Americans, every country but the government's become much stricter and also the economy's not so good. Before it was easier to give higher wages, but now it's not," she said.
The authorities do seem to be tightening up the immigration rules. In the past many women worked in the entertainment districts illegally on tourist visas.
That is not so easy these days.
The immigration department says it has introduced more rigorous checks on young women arriving from certain countries where they suspect significant numbers of illegal workers are coming from.
Since 2005 new measures to combat human trafficking have also been introduced.
Monina said there was only so much a mama-san can do to ensure the safety of the girls who work for her.
"It's really the girl's responsibility. There are certain rules that you teach the girls, how to tell who is a good, who is a bad customer for instance, but you cannot control what they do out of hours. After the club closes it's up to them to decide how far they want to go with the customer," she said.
Hostess bars are part of the mainstream of Japanese culture. Business deals are done there and clients entertained. Wives know they are part of life for "salarymen".
But when you sit there and watch the young women cuddling up to the older customers, or so drunk they can barely keep standing to finish their song on the karaoke machine, you wonder whether it really is that innocent.
Of course there are establishments far more sleazy than the one we visited.
As Japanese journalist Kentaro Katayama points out, if a salaryman is looking for sex a hostess club is not necessarily the best place to find it.
He said: "If you really want to have sex with somebody it's much easier to go to a prostitute.
"Going to a hostess club would cost you more than meeting a prostitute in Tokyo. It is very expensive, and yet still people like to go."