"My family cannot go back to the country," Yusuf wrote in a letter addressed to AFP this week. "My mother cries all the time, and my three-year-old brother does not eat."

Yusuf, who did not want his real name used because of his family's sensitive status, has despite his young age repeatedly collapsed from stress linked to the family's legal problems.

His brother has been treated at hospital for asthma and a high fever, apparently from the shock of witnessing his father being taken away by some 20 immigration officers.

Yusuf is one of a growing number of Turkish Kurdish children living precariously in Japan, where their parents wage court battles for legal status that often take years and almost always end in defeat.

Japan, as a leading democracy in Asia, has had a growing pull for Kurds fleeing Turkey, especially since the late 1990s when European nations tightened their immigration policies, and in part since Japan emerged as a major donor in the region following the first Gulf War.

But not a single one of several hundred Kurds who have applied for refugee status in Japan has succeeded in a country that has never welcomed large-scale immigration.

Instead, suburbs north of Tokyo such as Kawaguchi have developed a small but growing Kurdish population, where a community with shaky residency status came together to feast in a park in March for the Kurdish New Year.

Yusuf's father came to Japan with his wife and two boys in October 2006, seeking asylum as he said he faced persecution back in Turkey, where Kurds have fought for years for greater cultural rights.

"The entire family has lived in Japan on a temporary status while the refugee application was being processed, but the immigration office decided last week not to allow them to stay," said immigration lawyer Takeshi Ohashi.

"It's only the husband who is being detained right now, but the wife may also be taken into custody, which inevitably would send the children to a public institution," said Ohashi, who has long helped Kurds of Turkish nationality in Japan.

Yusuf's father earlier spent 13 months in Japanese detention until being freed last year pending proceedings on the family's asylum application.

"I am constantly worried about what would happen to my dad and family," Yusuf had told AFP in an interview before his father was detained.

Although he loves playing baseball and swimming, the little boy has collapsed twice before.

He fell to the ground during physical education classes with white foam coming out of his mouth, said his 29-year-old mother, looking on as her son played a handheld computer game with other Kurdish children.

"The doctor said he suffered excessive stress," she said.

As years go by for Turkish Kurds without a stable status here, many of their children have assimilated in the local community.

In the city of Kawaguchi alone, 14 children of Turkish nationality were registered at local elementary and middle schools this year, nearly tripling in two years, a local education board official said.

The number is significant for Japan, which has historically seen itself as homogeneous. Japan in 2007 accepted only 41 political refugees out of 816 applications. Thirty five of those accepted were from Myanmar.

In a rare move, Japan said in March it was giving residency to a Turkish Kurd, his Filipina wife and their daughter after the immigration authorities came under fire for trying to deport the family to separate countries.

But in 2005, Japan came under international criticism for deporting to Turkey two members of a Kurdish family even after the United Nations had recognised them as refugees.