"Commanders became concerned that soldiers wouldn't dare stand outside at night or use their weapons," says Chen, author of 14 ghost books, including "Ghost Talk in the Army."
A Defense Ministry official said the agency had no official comment.
"Our concern is defense readiness, not responding to superstition," he said.
Soldiers aren't the only ones looking over their shoulders. Some people admit to altering their behavior to minimize the chances of being attacked by rogue spirits.
This is especially true during midsummer ghost month -- the seventh month of the lunar calendar -- when the gates of the underworld open and the living burn paper "money" and delay weddings, medical procedures and even swimming because of the potential for bad luck.
This year, because of a calendar anomaly, there's a double ghost month, from July 25 to Sept. 21, extending the time the spooks are out wandering around.
Facing the prospect of a long drought, some wedding halls have cut their ghost-month prices 15%.
The summer ghost periods of the late 19th century are notorious for near-riots. Young thugs would claw at one another to steal the offerings left for spirits. In 2003, media reported a new twist: shops hiring bikini-clad women to sing and dance for the hungry souls, also known as "good brothers."
Chen Jun-jie, 18, a high school student, says he keeps his windows and doors shut tight year-round so the spirits can't peek in at him.
"I'm quite careful about ghosts," he says, dressed in Nike sneakers and a matching basketball outfit. "I once had one sleep on me, and I couldn't move for a long time."
Su Jeou-jin, 33, a civil servant, avoids mountains at night, whereas homemaker Chan Ching-fen, 33, won't swim in the dark. As added insurance she buys a temple talisman, she adds, pointing to a red, prayer-inscribed card pinned to her baby's blouse.
Anthropologists say that in China's rich spirit world, gods tend to be honored, ancestors tend to be honored or appeased, and ghosts tend to be appeased or avoided.
In this ancestor-worshiping culture where the memories of the living nurture the dead, tormented ghosts are often the embodiment of people with few loved ones to remember them, and of those less connected to their clan. They include unmarried women and people who die violently or far from home.
"Ghosts are in a sense gods that have fallen out of the system," says Robert Weller, research associate with Boston University's Institute on Culture, Religion and World Affairs. "They're desperate."
Scholars say the layers of hell in the Chinese belief system closely resemble in structure the former levels of imperial government, while ghost hierarchies mirror old bureaucratic rankings headed by a king of ghosts.
"This is endlessly complex, fascinating and expressive," says Steven Sangren, an anthropologist at Cornell University working on a book about ghosts and psychology.
The ghosts often have grotesque features, such as pointed heads, large, black teeth and faces without noses, chins or lips. And they love to whistle or knock on doors, or blow noxious fumes on you.
Hardly an area of Taiwanese life is untouched by their ghoulish breath, including the criminal justice and business worlds. Construction crews apologize to wandering ghosts before blowing up mountains or moving dirt. Police occasionally suggest that an unsolved crime is complicated by "unexplained phenomena."
And courts in Taiwan periodically hear cases in which defendants claim that ghosts told them to commit crimes, although these arguments don't tend to carry much weight.
Tsai Mon-hua, head of sales at Yong Ching Realty in Tainan, says almost every client looking at properties wants to know if someone has died there or if the place is haunted. The unconvinced can check websites that list properties susceptible to paranormal events. Occasionally, unscrupulous buyers spread ghost rumors hoping to drive down prices. "But only a few houses are so-called haunted," Tsai says.
Politics are not immune. In July 1996, Taiwan's now-defunct provincial assembly, which used to oversee local government, held a three-day ceremony to drive away evil spirits some considered responsible for nearly one-third of the 79 deputies being indicted for corruption or vote rigging. A Taoist priest danced and brandished a knife while 12 basins of towels were placed before an altar so the ghosts could cool off in the summer heat.
Although sociologists say Taiwan has seen some gradual weakening of traditional beliefs, given better education and wider use of technology, its ghost world has been surprisingly resistant to the erosive influence of globalization and MTV.
More young people are reportedly returning to traditional beliefs in reaction to what they see as excessive consumerism. In the survey of Taiwanese college students by the Chinese Culture University last year, which involved 1,144 people at nine universities, 16% said they believed they would become ghosts after they died. And half thought it was possible to contact the dead through a seance.
Outsiders sometimes see a contradiction between the ultra-pragmatic side of many Chinese and the almost poetic world of ghosts.
"It's sometimes hard for Westerners to understand," says Lin Mei-rong, a sociologist with Academia Sinica, Taiwan's preeminent think tank. "But look at all those saints the Christians have."
Special correspondent Tsai Ting-I contributed to this report.