Graying and overweight, many of the engineers look nothing like the crack Imperial Army troops that terrorized much of the region nearly 50 years ago. That was the point. Their real job is to make sure nobody in Asia is reminded of World War II. Japan’s intense preoccupation with the deployment is a measure of just how gun-shy the country has become since its last foreign adventures led to catastrophe. “Everyone in Japan is watching every activity big and small,” said one senior military official. “So we are very tense.” For the government, a setback would threaten plans to begin reasserting a world role with manpower as well as money-under the U.N. umbrella. Last June Tokyo won parliamentary approval for the eventual deployment of nearly 2,000 troops only by arguing, in effect, that these soldiers aren’t really soldiers at all. They will build roads. So the brass are going to great lengths to stick to an unsoldierly, Grated script.

Any Japanese soldier caught in Phnom Penh’s booming brothels will be shipped home, the military warns. Unlike troops from other countries, the Japanese won’t be given condoms. AIDS isn’t the only issue: the subject of sex is ultrasensitive because of disclosures this year about how Japanese troops held “comfort women” in Korea and China during World War II. The soldiers have been ordered to respect the locals; they are not to pat children on the head or throw them scraps. Military planners expect to keep the troops happy with video letters from home, a high-tech rec center equipped with karaoke studios, a well-stocked bar and carefully chaperoned trips to such cultural sights as Angkor Wat. So far, complaints have been minor. Grumped one soldier: “No showers.”

Like sex, violence is out. The engineers’ base in southeastern Cambodia is as far as possible from the Khmer Rouge troops who are violating the terms of a peace treaty signed last October. Because Parliament expressly forbade Japanese troops to clear mines, remote-controlled bulldozers will be used. Still, the deployment remains a gamble. Eight Japanese military observers will be directly in harm’s way-posted to heavily mined border checkpoints in northern and central Cambodia, where Khmer Rouge guerrillas remain active. Three U.N. peacekeepers already have died of malaria this year. “We must become accustomed to a more dangerous role,” said one Japanese Defense Agency official. But any casualties–or scandal–could badly damage the prospects for a sequel.