WASHINGTON, Jan. 20 — In the log book at Task Force Dagger, the field headquarters for all Special Operations missions in Afghanistan, the following code was entered for Dec. 12:

"GRN-GRN AA022 EXFIL'D."

Green-on-green, it indicated: two anti-Taliban units fighting each other.

AA022: an Army Special Forces "A Team," code-named Cobra 22, caught in the middle.

Exfiltrated: time for the American soldiers to get out in a hurry.

The men of Cobra 22 had spent more than two weeks advising Sayed Jaffar, a warlord of the Northern Alliance whose forces helped push the Taliban out of the northern city of Kunduz.

The town fell on Nov. 26, but the region was still dangerous, and now the nearby village of Pul-i- Kumri erupted in gunfire as the Jaffar militia confronted the troops of another anti-Taliban warlord. It was the kind of violence that for years had hampered the resistance.

Seeing no military logic in refereeing the dispute, American commanders rushed an MC-130 Combat Talon transport plane and two Black Hawk helicopters to extract the Special Forces from the scene. For good measure, an AC-130 gunship, bristling with rapid-fire cannons, flew shotgun.

American Special Operations forces in Afghanistan, whose experiences are reshaping war- fighting doctrine, faced many obstacles — foul weather, strange allies, friendly fire and, of course, the enemy. And many in the military were surprised at how much they have accomplished.

Even as the war entered a new phase with the first use of American ground troops in late October, senior commanders were unsure that sending a few dozen advisers into the fight could topple the Taliban and cripple Al Qaeda. They were ready to throw much larger numbers of conventional troops into combat.

The ground campaign opened on one of the darkest nights of the war, four days past a new moon. And when the sun rose the next morning, on Oct. 20, two very different operations had been completed, as if to illustrate the choice of methods that the Pentagon was considering.

But the Pentagon spoke publicly then about only one of the operations that occurred that night.

Just hours after the mission ended, the Pentagon announced that hundreds of Army Rangers had parachuted onto a military airfield about 80 miles south of Kandahar while a helicopter raid hit a Taliban compound at the edge of the city. Dramatic videotape of the airborne assault was broadcast.

But the Pentagon said nothing about a secret ground war — which quickly became the real ground war — that started simultaneously in the north.

The first two teams of Army Green Berets to infiltrate Afghanistan landed by helicopter that same night, according to Special Forces commanders who planned the mission. One joined up with Abdul Rashid Dostum, the war-calloused Northern Alliance commander near Mazar-i-Sharif, and the other with Muhammad Fahim Khan, now Afghan defense minister, whose forces were then loosely arrayed against the Taliban in the direction of Kabul.

More would follow, but it was not easy. During just the second mission to carry Special Forces teams into the north, the helicopters were unable to land because of a powerful sandstorm.

"I cannot even begin to describe the frustrations," a senior Special Operations commander recalled. "We were right there. It was like, just six more inches, but we couldn't get over the goal line."

But in just three weeks, those A Teams — as the Special Forces calls the detachments of a dozen select troops — transformed the Northern Alliance into a force capable of routing the Taliban army, which was increasingly damaged and demoralized by the more precise bombing that the American target-spotters made possible.

Few things surprised the Pentagon and its commanders as much as how rapidly the military picture changed with the arrival of the Special Forces. The prospect of fighting big battles with American troops faded away.

Brig. Gen. Richard L. Comer, vice commander of the Air Force Special Operations Command at Hurlburt Field, Fla., said the more conventional plan had been to "put in a large amount of American forces, hop them in by air."

The alternative, General Comer said, was to rely mainly on the native forces opposing the Taliban. The thinking, he said, was: "Let's start with that, see what they can do. Put Special Forces in there, knit them together, and see how good we can make it."

If it had not worked, the war might have seen many strikes by large forces of Rangers and other infantry. In a final push, marines were to seize Kandahar's international airport by force, senior officials said.

"We reasonably expected to do a lot more heavy operations," a senior Defense Department official said. "We might have seen more of those events like 300 Rangers dropping out of the sky on a given night. But the A Teams brought us a steady increase of pressure, and the sudden collapse of the Taliban. Nobody predicted that."

The lessons from the Afghan experience are already being adopted in the broader war against international terrorism. In the Philippines, scores of Special Forces are being sent to advise and assist its army in fighting terrorists. In the Pentagon's war rooms, contingency plans are being re-examined, and top officers are declaring that relatively small but highly proficient units, operating secretively and equipped with an arsenal all their own, can quickly change the balance of power.

But the war in Afghanistan has illuminated the risks, as well. Special Operations forces had to help quell a riot when Taliban prisoners rebelled, killing a C.I.A. officer. A helicopter that crashed in the mountains trying to evacuate a sick commando had to be bombed by an American jet to protect its secret equipment. An errant bomb killed three Americans of the Special Forces — and nearly killed Hamid Karzai, on the day he was appointed head of the new interim Afghan government.

And the only soldier killed so far by hostile fire was Sgt. First Class Nathan Ross Chapman of the Special Forces. His group was ambushed in Paktia while trying to stitch together an Afghan militia to hunt for Osama bin Laden and his Taliban ally, Mullah Muhammad Omar. That mission still has not been accomplished.

First Raid: Ranger Mission — 'Meat and Potatoes'

Meticulous planning for the first use of American ground forces in the war began in late September, after the Pentagon learned of a remote desert airfield within striking distance of Kandahar.

At Fort Benning, Ga., intelligence officers of the 75th Ranger Regiment pored over photographs from satellites, Predator drones and other reconnaissance aircraft.

They calculated the height of a wall around the compound from the length of its shadow, pinpointed potential Stinger missile placements and watched the movements of construction workers and Taliban troops.

Overnight on Oct. 19, four MC-130 Combat Talon airlifters dropped more than 200 Army Rangers on the airstrip, code-named Objective Rhino.

It would be a month before American forces, marines, would return to that base, and when they did, their role was largely to protect it so that Special Operations forces would have a staging point near Kandahar.

The Rangers shot and killed a fleeing Taliban soldier, scoured the empty compound for weapons, and collected some documents, few of which proved useful. American warplanes killed 30 Taliban near the airstrip.

"It was a meat-and-potatoes Ranger mission," said Maj. Robert Whalen, an intelligence officer of the 75th Ranger Regiment. "Seize the airfield in a lighting fast strike, and get out."

For most of the Rangers, mainly in their early 20's, it was their first combat. On the way into Afghanistan from their staging area in the Persian Gulf region, Staff Sgt. Timothy Shrewsbury recalled, a battalion commander led them in reciting the Ranger creed. "Surrender is not a Ranger word," it says in part. "I will never leave a fallen comrade to fall into the hands of the enemy."

"I know I wasn't scared," Sergeant Shrewsbury said. "It's such a cliché, but the training really does take over. It was like a big exercise."

Though smaller groups of Rangers would conduct other missions in southern Afghanistan — mainly calling in airstrikes against convoys — the first commando raid of the war was not to be repeated.

Unconventional War: Small Units Sent on Large Missions

The use of small, highly trained units to accomplish large, strategic missions by exploiting an enemy's weakness has been talked about for years, but tried with mixed success in the past. Initially, there was little reason to be optimistic about fighting this kind of war in the anarchy of Afghanistan.

Army Special Forces typically take months, if not years, to cultivate relationships with friendly regional powers. (The term Special Forces refers to the Army's Green Berets only; the phrase Special Operations forces encompasses the universe of unconventional warriors in all of the services.) While Special Forces had trained with some Central Asian militaries, they had never worked with Afghans, whose hostility to foreign armies goes back generations.

Before the war, the mission of attacking Mr. bin Laden and his supporters and bolstering the anti-Taliban resistance belonged to the Central Intelligence Agency.

The extent to which the Special Forces worked with the C.I.A. was another innovation in this war.

"We have more access at a more junior level to important intelligence than ever before," an Army Special Forces commander said. "What we are giving our teams in the field is much more than they've gotten before. In the past, there was a lot of information that was not given to captains and the A Teams. This time, they've got it."

The first question was whom to help, and it took weeks to answer.

"We basically had to figure out who was a `bad bad' guy, who was a `bad good' guy and if there were any `good good' guys," the officer said.

In the north, they chose from commanders who had kept their armies intact after the Taliban gained control of the cities. In the south, they looked for tribal leaders who could attract fighters to their side from the mainly Pashtun tribal groups. One such leader was Mr. Karzai, who infiltrated Afghanistan from Pakistan.

"We believed he had the most loyal following, but they weren't soldiers," said a Special Forces lieutenant colonel named Dave, who commands the teams that linked up with Mr. Karzai outside Kandahar, providing security and military advice. "They were shopkeepers and farmers and friends," said Dave, who like many of the unconventional warriors spoke on condition that his last name be withheld. "They would advance to the front in Toyota pickup trucks and Subaru taxis."

Getting uniforms, ammunition and food to those forces took time. But with American advisers at their sides, they took the offensive quickly. And with the Special Forces designating the targets on the front lines, the intense bombardment from the sky gave the anti-Taliban forces the ultimate advantage.

Air Operations: Even on Horseback, Calling In Strikes

Calling in air strikes is one of the most important jobs given to Special Operations forces.

When some 400 Taliban prisoners rebelled inside a fortress near Mazar-i-Sharif in late November, one of the first troops to rush to the scene was a 26-year-old Air Force combat controller, a staff sergeant named Mike.

An eight-year veteran from Oxford, Conn., the sergeant said he had pinpointed enemy positions and radioed for airstrikes by Navy F/A-18's carrying 2,000-pound bombs. It took them just 15 minutes to respond.

One of the satellite-guided bombs exploded only 70 feet from his position, hurling him into the air and wounding four other American troops. "Everything went black, and I thought I was dead," he said in an interview at the Hurlburt Field headquarters, where he is recovering from punctured ear drums, flash burns on his face and scratched corneas.

He was one of about 100 combat controllers, weathermen and search-and-rescue specialists then operating in Afghanistan, officials said. Trained to scout targets and spot them with laser range-finders, combat controllers advise pilots on what kind of bomb to drop and how best to fly to the target. They also identify landing zones for troops and drop zones for parachuted supplies.

Each of them carries 150 pounds of gear, including radio and navigation equipment and, of course, a rifle. The steep mountain trails of Afghanistan presented challenges, Mike recalled. "I've trained for a lot, but this was the first time I ever rode horseback," he said.

Evolving Doctrine: Wholesale Integration in Air and on Ground

While the use of Special Forces to build an opposition army in Afghanistan was straight from the doctrine of unconventional warfare, their wholesale integration into the air war was unusual, according to senior military officials involved in the planning throughout the conflict.

"The guys on the ground were originally conceived as developing classic liaison relationships with local forces with the goal being to build a groundswell of opposition," a senior military officer said. He said this "strategic" plan became more "tactical" as the Special Forces teams proved so effective at spotting targets for American bombers and attack jets. "We refocused our efforts," the officer said. "We did not expect they would play such a large tactical role."

But the path had been blazed in advance.

Last July, Lt. Gen. Maxwell C. Bailey, who until earlier this month was head of the Air Force Special Operations Command, created a permanent Special Operations liaison team ready to deploy on short notice to any regional conflict.

Twelve days after the attacks on the World Trade Center and Pentagon on Sept. 11, two dozen of its Air Force experts and three Army Green Berets arrived at Prince Sultan Air Base outside Riyadh, Saudi Arabia, to join the planning for the air war that started two weeks later.

Air Force Special Operations planes flew some of the most devastating attack missions.

The Special Operations cargo plane of choice, the MC-130 Combat Talon equipped with advanced terrain-following and terrain- avoidance radar, is also used to drop the 15,000-pound BLU-82 "Daisy Cutter" bombs.

The Combat Talons, flying 14.5-hour round-trip missions from their base in Incirlik, Turkey, also parachuted hundreds of plywood containers, each weighing 1,400 to 2,200 pounds and filled with food, winter clothing and small arms, to the anti-Taliban forces who would carry the brunt of the fighting.

Fratricide: Errant Bomb Kills G.I.'s and Afghans

On Dec. 5, three Green Berets and five of their Afghan comrades were killed when they were struck by an errant American bomb during the siege of Kandahar. Many more were wounded.

A fresh Special Forces A Team, code- named Python 33, was given just minutes to grab weapons and rucksacks and load onto an MC-130 for the flight to the marines' forward base, Camp Rhino. Even before they touched down at the desert airstrip, a transport helicopter and two attack helicopters had their rotors spinning for the trip to the front.

"There was none of the Army's hurry up and wait that day," said Randy, a sergeant first class and the Python 33 combat medicine specialist.

They arrived just hours after the fratricidal bombing, and the offensive on Kandahar continued.

There are many visible reminders of what happened: Major Don, deputy commander of Special Forces in the Kandahar region, still limps from wounds he received on Dec. 5, but he refused to leave Afghanistan. And the men of Python 33 still drive a white truck, its windshield blown out and its panels pocked by shrapnel from the errant bombing.

And some are less visible. One night just outside Kandahar, a member of Python 33 produced an armful of mail from his pack. He had just heard how the remains of one Green Beret were taken home with a letter from his wife still in his pocket.

"If I don't make it home, I don't want these letters coming home with my personal effects," he said, as he pitched a fistful of holiday cards and notes into the roaring campfire of the Python 33 base in the compound where Mullah Omar once ruled.

Lessons Learned: Uncomplicating Chain of Command

For years, the Pentagon has struggled to blend Special Operations forces — with their distinctive training, their peculiar weaponry, their unorthodox tactics and their culture of secrecy — into the joint operations of land, sea and air forces. In the Afghanistan campaign, this was a goal from the start.

Unconventional warriors have their own unified combatant commander, Gen. Charles R. Holland, who heads the Special Operations Command. Among the distinctions of his command: It is the only one in the military with its own research and development budget. But General Holland played a much larger role in the Afghan campaign than simply readying and providing those forces.

In combat, his units came under the command of Gen. Tommy R. Franks, the commander in chief of the Central Command, who is in charge of all military operations from the Horn of Africa to the Hindu Kush. Under him is Rear Adm. Albert M. Calland 3rd, the Special Operations commander in the region.

A complicated chain of command is anathema to warriors, but the day-to-day reality of this arrangement was not so complex. General Franks' headquarters in Tampa, Fla., is literally next door to the headquarters of the Special Operations Command. He and General Holland speak virtually every day, and planned the war together.

Their civilian boss, Defense Secretary Donald H. Rumsfeld, likes to joke that he hates to say things twice, so he, General Franks and General Richard B. Myers, chairman of the Joint Chiefs of Staff, speak together at least twice a day to discuss jointly all aspects of the war campaign.

The war was as unpredictable as any other, but there is little sign that the commanders struggled over the use of unconventional forces.

But in the ranks and among the commanders, there is talk that the $3 billion spent each year to field and equip 40,000 Special Operations fighters is not enough.

"When our group was notified to prepare for deployment, there was a huge spastic response to procure items we should already have had — in communications, global positioning systems, cold weather gear," said one Special Forces major, named Chris, interviewed in Afghanistan. "We were taking off for Afghanistan, and in the back of the cargo plane we were still practicing on our new satellite phones. Stuff is still arriving now, and I think, `Hey, this would have been great four weeks ago.' "

A senior Defense Department official explained that Mr. Rumsfeld and General Franks had made a conscious decision to move fast despite the risks.

"There was a clear decision made not to wait for a stately buildup of forces to the brink of combat, and only then to walk through the wall," said a member of Mr. Rumsfeld's inner circle.

The campaign exposed a shortage of aircraft to refuel helicopters on long missions, General Bailey said. He said the Air Force would like the CV-22, a variant of the Marine Corps' Osprey, a new aircraft that has been delayed by serious technical problems.

But General Bailey, like other Pentagon leaders, cautioned against thinking of Afghanistan as the model for all future wars.

"In my mind, you have to be very careful about trying to apply too specifically the lessons of Afghanistan," he said. "We've had a very successful campaign, with air power, surrogate forces with Special Forces. We can duplicate things under our control, like air power and Special Forces. But where are those indigenous forces? Where does that exist in other places in the world?"