"Okay, look at the map," said Capt. Tim Krawczel, a Special Forces officer with the Maryland National Guard. "Which way is that creek flowing?"

"Up, sir?" replied a soldier gesturing at the top of the map.

"Up? Can water flow up?" Krawczel shot back. "That's north."

Krawczel rolled his eyes and continued briefing squad leaders of Charlie Company on map-reading techniques that would be used during night patrol. It was to be one of the toughest exercises in the two days of drills held here last weekend by the First Battalion, 115th Infantry Division of the Maryland National Guard

"I think they can do it," he said later. "But it's not going to be real easy."

The training exercises -- staged in the 90-degree heat in densely wooded hills of Western Maryland 95 miles west of Washington -- were the first in a series designed to transform Charlie Company's weekend warriors, who live in the Washington area, into skilled fighters of the newly reactivated 29th Light Infantry Division.

The division, which incurred some of the heaviest casualties on D-Day during World War II, was deactivated in 1968. Its rebirth was announced with great fanfare by Defense Secretary Caspar Weinberger in June on the 40th anniversary of the allied landing.

The concept of highly mobile light infantry, skilled in the art of guerrilla warfare, was developed by Army Chief of Staff John A. Wickham Jr. for quick-hit combat situations such as the 1983 invasion of Grenada.

Four new light infantry divisions will be made up of regular Army units, but the fifth -- the 29th Division -- will be manned by guards from Maryland and Virginia.

The honing of part-time soldiers like those of Charlie Company into a combat-ready fighting force also tests the National Guard's ability to supply troops, said Maj. Howard S. Freedlander, a guard spokesman.

That point was not lost here on the troops or the officers of the First Battalion, who trained with what many said was unusual zeal, despite an occasional glitch.

"The first time you do it, you look a little awkward. This is an orientation for the troops to get their minds set in the right direction so they know what's expected of them," said Lt. Patrick Kinsey, a company commander, who works as a photographer in Baltimore.

As a helicopter loaded with Army brass buzzed overhead, more than 300 men from Baltimore City and the Washington suburbs went through the training exercises.

Special Forces instructors demonstrated how to rappel down a 90-foot cliff, cross the Potomac River on a rope bridge and scale the vertical rock face of a hill.

They also taught land navigation, map reading and combat patrolling techniques.

"This is a first-time experience for me," said Sgt. Lloyd Mason, 49, of Landover, who has been in the guard for 17 years. "A lot of the men have not done this before."

"This is really good training, where you can put your hands on and really get to it," said Cpl. James Berry, 29, a Marine veteran from Silver Spring who is studying at Georgetown University to be an emergency surgical technician.

The point of the training is to develop troops who can be mobilized quickly -- within three days, instead of the 10 days needed for regular divisions -- and fight up to 72 hours without resupply in all kinds of terrain and conditions, according to an Army white paper.

Light infantry will not have the support of tanks and heavy artillery. Instead, it will rely on ambush, night strikes and stealth, an Army spokesman said.

Many of the troops seemed excited about the idea. During breaks in training they talked about the possibility of seeing combat, their girlfriends, the food and the camaraderie of belonging to an elite unit.

"It's like any change; you look forward to it because it's new," said Thomas Villemi, 23, an apprentice electrician.

The thought of going into combat "is in your mind but not all the time," he said.

"Yea, you just think about it once a month," added James Loudin, 19, of Falls Church.

"Wherever they decide to send us, we have to be prepared to go," said Mason. "My wife is concerned about it. She's even concerned when we go out training. She just says, 'Don't get hurt.' "

The weekend exercises were designed "to create a warrior spirit," said Lt. Col. Steven Blum, the battalion commander who is charged with the task of whipping the guard units into shape.

To practice the various skills, the company was broken down into platoons. Despite the heat, most troops wore heavy camouflage uniforms that were found to be unsuited for tropical climates during the invasion of Grenada.

"Without the gear, this outfit weighs 13 pounds," said Sgt. John Goheen, a part-time University of Maryland student.

At one training station, soldiers splashed into the Potomac River and pulled themselves across using a rope connecting the two banks.

"How deep is the water?" asked one private before taking the plunge.

"Deep enough to drown," said Special Forces instructor Richard Christopher of Baltimore.

The river, which flows placidly in that area, was five to eight feet deep. Soldiers who could not swim wore life vests, although these would not be available in combat, Christopher said.

The exercises looked difficult, but most are designed with an extra margin of safety, said one officer.

Midway through the exercise, for example, Blum ordered the night patrol routes shortened by more than half because hazardous terrain was discovered during an aerial reconnaissance of the area.

"I want to build winners. The only way to get confidence is to succeed at what you do. But don't put them down," he said. "They're better than the regular Army. They are older, more mature and they're smarter. I have people running their own businesses."

By the end of the day, the only injuries to the troops were two sprained ankles and one case of heat exhaustion.

The typical soldier in the Maryland Guard is 23 years old. Most have a high school education, and many others have college degrees or college training, Kinsey said.

Many joined after serving regular tours in the Army or Marines. Most received a $4,000 bonus to sign up.

Guard units train one weekend a month and two weeks every summer. Soldiers are paid anywhere from $90 to $150 a weekend. Officers get more.

"The check just about pays the mortgage," said Krawczel, a zoning administrator in Loudoun County, who joined the guard at 29 after a tour in the Peace Corps.

"I just said, hey, I need another dimension in my life," he said. "This was it."