NEW YORK, N.Y. -- On Sept. 29, 1918, the New York National Guard Soldiers of the Army's 27th Infantry Division fought their way into the defensive works known as the Hindenburg Line.

The attack did not go smoothly and casualties were high.

At a cost of 3,076 men wounded and killed over two days -- out of the division's strength of 18,055 -- the New Yorkers fought through a maze of German machine gun nests and fortified positions to captured the leading edge of the main German defenses.

One unit, the 107th Infantry Regiment, famous as the 7th Regiment of the New York National Guard, lost 396 men killed and had 753 men wounded out of a total of 1,662 Soldiers who began the battle.

The costly attack, though, broke open the main German defense in northern France and opened the way for the British Army to go on the offense.

By the end of September 1918, most American Soldiers in France were part of the First American Army commanded by Gen. John J. Pershing. But the New York National Guard's 27th Division and the 30th Division, made up of National Guard Soldiers from several Southern states, had been "loaned" to the British Army and fought under British command as the II Corps.

They'd fought their first battle at the end of August 1918 and then pulled out of the line to begin training for this major assault.

The Americans were new to combat in the Great War, but they had one thing the British, and the Canadians and Australians that fought with the British, did not have -- numbers.

American divisions were twice the size of British army divisions, and British Field Marshal Douglas Haig knew he needed numbers for this assault.

For this battle the Americans were placed under the command of Australian Gen. John Monash, considered to be one of the best commanders of the war.

Like the Americans he commanded, Monash was a part-time soldier. He was an engineer in civilian life but was an officer in the Australian militia.

When he went to wa,r he learned fast. He was successful without spending the lives of his Soldiers.

The plan Monash came up with called for the 27th and 30th Divisions to lead the attack. Their large divisions would make up for the fact that two of his Australian divisions were effectively out of the fight.

The Americans would take the St. Quentin Canal and then two Australian divisions would follow up and leap-frog through the Americans to finish the assault.

A key feature facing the Americans was a 3.52 mile long tunnel through a mountain. Inside the tunnel the Germans were using old barges as barracks. The Germans could wait out the artillery and then pour out to counter-attack.

At the beginning of August the Americans were pulled out of the line and began training for the fight. They learned to work with British tanks. The tanks were critical because they were supposed to provide firepower for the advancing Americans.

Monash sent 200 Australian officers to work with the Americans and make sure they understood how he would fight the battle.

It could have made for hurt feelings, but the Americans and Australians got along. They both thought the British officers were a bit snobbish, but they liked each other.

The plan called for the Americans to launch a preliminary attack and move up to a set line on Sept. 27. This "start line" for the main attack was what drove the plan for artillery barrage, which would cover the Americans on their attack.

But things did not go as planned.

The British division to the north of the 27th Division did not advance as far as it should have during the preliminary attack. The Americans of the 106th Infantry Regiment, which led the attack, started further behind than they were supposed to and did not reach the planned start line for the Sept. 29 attack.

Casualties were heavy. In one battalion every officer was killed. They held the ground where they stopped.

This meant American Soldiers were holding the line in locations where Allied artillery should be falling to allow the 107th Infantry Regiment to attack. In World War I communications were so slow that artillery fire had to be planned well in advance. There was no easy way to adjust fire.

So on the morning of Sept. 29, the Americans would have to move more than a half mile in the open before they caught up with the artillery barrage.

At 5.55 a.m. on Sept. 29, the attack began. The 107th Infantry Regiment attacked on the left of the 27th Division front while the 108th Infantry Regiment attacked on the right.

Artillery fire fell on the Germans, but not the Germans right in front of the Guardsmen. The American Soldiers kept attacking, but they took heavy loses.

The tanks that were supposed to provide fire support got knocked out by artillery fire, and in some cases, old British mines. The Soldiers were pinned down by German machine gun fire and counter-attacks.

The 107th Regiment continued to attack, but took very heavy loses.

"They were more than seasoned veterans," Maj. Gen. John O'Ryan, the commander of the 27th Division wrote after the war, "for in addition to battle experience and technical training they possessed in fullest measure pride of organization, high sense of honor and a strong sense of accountability to the home land and the family."

"The roster of the dead contains the best names of the city of New York--best in the sense of family tradition and all that stands for good citizenship in the history of the city. This comment applies as well to the rest of the remainder of the regiment and in the same way to the remaining units of the division, which represented other cities and localities of New York State, "he wrote.

The well-tuned plan fell apart and the Soldiers fought in small units and companies.

The fighting was often hand-to-hand, which surprised the Germans. By the afternoon of the 29th some of the 27th Division units had reached the St. Quentin tunnel. But others were still pinned down.

Gen. Monash blamed the Americans for not sticking to his plan. The Americans, Monash told an Australian war reporter, "sold us a pup … They're simply unspeakable."

The confusion on the ground made it impossible for the Australians following the 27th Division to leap-frog through the Americans, and Monash directed the Australian units south of the St. Quentin Tunnel where the 30th Division had better success.

In other cases Australians joined members of the 27th Division in the attack.

Historians, though, say Monash was unfair to the men of the 27th Division. Because they were not able to start the attack where they should have, their lines were thin and they had to advance further than they should have.

The fighting continued on Sept. 30 and the Germans began to give away. By Oct. 1, 1918 the Americans and Australians had cleared out the fortifications.

After the war, and outside of the heat of the battle, Monash was generous to the men of the 27th Division.

"I have no hesitation in saying that they fought most bravely, and advanced to the assault most fearlessly," he wrote.

"The leaders, from the Divisional Generals downwards, did the utmost within their powers to ensure success. Nor must the very bad conditions under which the 27th Division had to start be forgotten. Our American Allies are, all things considered, entitled to high credit for a fine effort," Monash wrote.

During the World War I centennial observance, the Division of Military and Naval Affairs will issue press releases noting key dates which impacted New Yorkers based on information provided by the New York State Military Museum in Saratoga Springs, New York. More than 400,000 New Yorkers served in the military during World War I, more than any other state.