The deployment of 600 Japanese soldiers in the southern Iraqi city of Samawa, to provide humanitarian and reconstruction aid, marks the country's largest military operation since the end of World War II.
But the latest deaths add to the alarming rate of suicide within the 253,000-strong Ground Self Defence Force (GSDF), where 94 personnel (soldiers) committed suicide in the fiscal year 2004, 75 in 2003, and 78 in 2002.
This is almost double the national average in a country renowned for its suicide problem, with 24 per 100,000 people committing suicide every year - compared with America's 10 per 100,000.
Prior to the Iraq mission, defence agency records showed that the reasons for military suicides fell into five categories: Family-related (6); duty (10); and physical and/or mental illness (2).
Twenty-four suicides were categorised as "loans", and 36 as "other/unknown".
A spokeswoman for the defence agency says the main reason for SDF suicides is financial distress. "Personnel borrow large amounts of money and they feel they can't consult anyone with that problem."
Asked why so many personnel should need to borrow money, she said: "We don't know."
"We educate personnel about money problems with leaflets and videos. It is difficult [to] see the effects of the education ... the number of suicides have not reduced."
No specific reason
Maasaki Noda, Kwansei University's professor of psychopathology, says that in contrast to civilian suicide, it is very difficult to identify a specific reason for suicide in the military.
Nevertheless, he says a combination of Japanese mental vulnerability, bullying, and people management have played a role.
"Japanese people are mentally weak and therefore are not strong enough to mentally endure," Noda says.
The Japanese force in Samawa
has a humanitarian mandate
SDF recruits are not "elite" individuals, he continues. Most are high school graduates attracted by money, individuals struggling to find work, or those of an older generation looking for a secure job to see them through to retirement.
Noda also cites the former Imperial Army's penchant for hard treatment and training as a psychological factor.
"Features of disciplinarian war-time management have been passed down to today," he says.
Tsuyoshi Amemiya, a professor at Aoyama Gakuin University, agrees, saying young Japanese are particularly vulnerable because they have been raised in a comparatively affluent society.
After enlisting in the SDF, "they are very shocked by what they see there. Japanese people are very vulnerable to shock".
Makoto Konishi of the independent, former SDF personnel-managed, Trans-Pacific GI & SDF Rights Hotline, believes military suicides result from depression caused by bullying and, importantly, the inability to escape from bullying.
"Yes, loans account for a great many suicides, but it is bullying that leads to personnel taking out loans," Konishi says. Konishi refers to several court cases where documents were made available to the public after investigation by bereaved families. "It's obvious the main reason is bullying."
Konishi says the bullying is intensified by the SDF's insistence that, upon signing up, personnel are required to sign a pledge promising that they will not quit before the end of their tour of duty. "In a regular job, quitting is easy. In the SDF, quitting is unlikely to be permitted."
"Japanese people are mentally weak and therefore are not strong enough to mentally endure"
Professor of Psychopathology,
The defence agency denies any such pledge, yet Konishi continues: "We get a lot of calls from people who want to quit but they are prevented by their superiors. Then they suffer depression and can't take the pressure."
"There are reports that there is bullying," the defence agency spokeswoman admits, "but we do estimate the main cause of suicide is money."
Japan's involvement in the Iraq war is also adding to the emotional distress.
It is the first time since Japan's 1945 surrender that its military has been active in a combat zone, Japan's post-war pacifist constitution permits the retention of a purely defensive military only.
Since December 2003, a total of 7000 SDF personnel serving on a rotation basis have been engaged in rebuilding the infrastructure of Samawa. They have not fired a single bullet or suffered any casualties.
"According to a survey by Kyodo news," the defence agency spokeswoman says, "70% of Samawa residents support the SDF and hope they will continue their activities".
On May 1 Fukushiro Nukaga, the Japanese defence agency's director-general, said Japanese military personnel would only withdraw from Iraq if and when British and Australian troops did so.
But Japan's deployment has caused much domestic dispute, with Junichiro Koizumi, the prime minister, side-stepping the constitution by insisting that the SDF have no fighting involvement and are present solely in a peacekeeping role.
Consequently, the SDF has gone to Iraq without the full support of the Japanese public, with many saying the dispatch is purely diplomatic and politically motivated.
Koizumi's decision to send troops
lacks the public's full support
Furthermore, with a constant US military presence in Japan, the SDF has been regarded by some as a superfluous, impotent army.
Taken together, Noda says this "reduces the sense of mission and lowers their pride", propagating a ''what's-the-point'' attitude after such intense training, and leading personnel to "question their achievements" when on return they are not met with a hero's welcome.
In addition to stress caused by the reality of being in a life-threatening situation, experiences of war can lead to post-traumatic stress disorder and maladjustment on return to civilian life, resulting in social and behavioural difficulties including homelessness, violent crime, and suicide.
"Heightened by confidentiality-imposed silence, this stress is subsequently mismanaged by the SDF," says Noda. "This affects the soldiers' lifestyle leading to recklessness."
Military records show that in 2002 SDF disciplinary action included 12 for insubordination, 241 for unauthorised absence, 15 for violent conduct, and 15 for manslaughter.
Signing up for active service such as in Iraq is done on a voluntary basis, and the soldiers undergo preparatory training which lasts for several months, during which time "anyone can quit", says the defence agency.
This training involves stress management, with further psychological support provided before, during, and after operations.
Prompted by the rise in suicides in recent years, the defence agency has also started to actively promote counselling by introducing a help hotline.