Tokyo police simulated what it would be like to work during a disaster Saturday by sending its 20,000 policemen to work on foot.

Saturday's quake drill, held by the Metropolitan Police Department, was based on the assumption that transport systems in Tokyo's 23 wards would be severely damaged in an earthquake of lower six on the Japanese earthquake intensity scale.

Police officers who live in a 10-km radius from their duty office walked to work, while those living beyond that range were allowed to partly use trains.

The drill, the second of its kind by the MPD, started at 6 a.m.

Some police officers in Chiba Prefecture used traditional passenger boats called "yagiri no watashi" to cross the Edo River to Tokyo's Katsushika Ward under the assumption that a bridge connecting the two sides was destroyed.

The traditional boats used to be a major means of transportation during the Edo Period but are now used as tourist attractions.

"We hope the drill will help our members acquire a sense of distance between their home and their work place," a MPD official said. "This way, they will be able to quickly decide what to do in the event of an earthquake."

In a lower-six quake, people find it hard to stand up and heavy furniture falls over.