Viewing a single comment thread. View all comments

mobilgroma t1_j1iqw6i wrote

Why did armies have a vanguard? Why is it separately named to the rest of the army and not just a part of it?

5

bradnelson t1_j1irub0 wrote

Sending a smaller unit out ahead of the main body is primarily done to locate the enemy and scout positions. A smaller unit is more mobile and can fall back to the main body. Sometimes you want your enemy to chase the vanguard as it retreats so that your main force can then attack the enemy from favorable ground. Very commons in Napoleonic and American Civil War era tactics, though you still see good examples of it in the world wars.

12

mobilgroma t1_j1isbia wrote

Thanks for the quick and very good reply!

And because they do different things than the main army, they are organised and named differently?

1

bradnelson t1_j1ix5gs wrote

Essentially, yes. There are variations on this based on the time period (and thus technology) as well as the theories of any given army. But broadly speaking, a vanguard could be any given army unit that is simply assigned that task. The next time they advance, it could be a different unit serving as the vanguard. Some armies might prefer to make the same unit the vanguard on a regular basis and train/equip it differently because of that. In some instances, it might be sending horse cavalry out ahead of the infantry, or it could be a specialized tank unit in WWII. I tend to think in the context of the American Civil War, so I typically picture infantry units ("skirmishers"). Usually they want to clear out any enemy units separated from the main enemy force (stragglers, scouts, or the enemy vanguard). Depending on who intends to go on the offensive, the vanguards might engage each other in a minor "battle" but they are never intended to carry out a proper fight, only to "feel out" the enemy, get them to retreat to avoid the main force, prevent the enemy from gathering intelligence about the size or position of the main force, or like I said before to coax the enemy into an attack on an entrenched main force.

2

jrhooo t1_j1mgk7o wrote

Depends on time and task.

To steal from wikipedia here, an example of a Middle ages vanguard (literally “advance guard”) would have been the ubits tasked with first up duties. So..

Scouts

Engineers (to clear obstructions from the road)

And even some messengers/diplomats (to reach towns first and basically say “ok, the rest of the army is coming up, do you guys want to just surrender now? Or do we have to bother setting up the whole siege thing? Come on. Save us all a headache and just surrender eh? We’ll give you a nice deal)

1

jrhooo t1_j1ml00l wrote

If you read the BOOK Generation Kill, they have good sort of example of this. (The TV Show is good but incomplete. It doesn’t explain whats happening as well)

But basically, on the initial invasion of Iraq, 2003, it LOOKS LIKE a Marine Corps Force Recon unit is being used as a traditional maneuver element, and (per the perspective of the book) being put in some needlessly risky positions, like obvious ambush routes.

Later the book sort of explains that the main force was on a “speed run”.

The Iraqi army was large, but notoriously disorganized and bad at command and control, SO the Allied war plan was speed. Overwhelm the Iraqi army and move too quickly for them to organize and coordinate defensive lines. Thus taking most of the country without a fight, and minimizing casualties all around.

Problem: slowing doen was not an option. Getting bogged down = giving the Iraqis a chance to regroup and dig in, snd them having to slug it out more often.

(In the words of Gen Mattis himself, in the prebrief, moving slow was a good way to land in an unpleasant convo with him. See: the Colonel he fired on the spot for getting stuck at a bridge)

So, SPEED

They were worried the Iraqis had a bunch of delaying ambushes set up that would bog down the main force

The Recon units were (according to the book) actually decoys, meant to trick the Iraqis into springing their ambushes early, so that your main force could just bypass them.

Hell of a tough task for the recon guys, BUT the whole idea dis that your toughest, best trained guys are the ones able to

A - lay down enough orce snd firepower for them to bluff an opponent into thinking they are a full sized unit

B - go around finding and baiting ambush positions, and actually survive doing it.

1

elmonoenano t1_j1j3cxc wrote

Besides the main reasons /u/bradnelson mentioned, sometimes they would be used to tie down an army. The Battle of Gettysburg is a good example of this. Lee was trying to avoid an engagement while his forces were concentrated and Meade was reluctant to do anything b/c he was worried about the political ramifications on his job for any action. Meade's vanguard was lead by John Buford and he knew Lee had to go through Gettysburg. So he got there and started setting up defensive lines. His Confederate counterpart, Pettigrew spotted him while scouting and went and reported back to his CO, A. P. Hill. Gen Hill didn't believe him and set out a larger scouting force. This gave Buford an opportunity. He had just a small force, they weren't really supposed to engage, the main force of the Potomac was still a day or so away. But Buford used the time between running into Pettigrew and the second scouting force to set up defensive works and pick the best positioning. When that scouting force pulled up, they saw the force wasn't large and the two sides engaged each other. Buford did well enough that Hill diverted more forces from the withdrawal to Gettysburg, and as they showed up the beginning of the AoP start to show up. The whole thing snowballed from there.

Buford, was able to force Meade to commit, by drawing Hill, and then the rest of the AoV into the fight.

/u/wetworth on the /r/civilwar made this for me, the other day to give you an idea about Meade's whole vibe during the battle. https://imgur.com/a/yuskW8r

4

bradnelson t1_j1kflxp wrote

John Reynolds played a role in this too. Buford’s cavalry was the true vanguard, though Reynolds was in command of the advance corps (Meade’s various corps were all strung out at this point and not unified in preparation for a battle). His orders were explicit not to bring on a general engagement, which made sense given the state of his army. Meade also wanted to fight back at Pipe Creek, some 20 miles southeast, and had issued orders to ultimately draw his army together there. To fight in Gettysburg would mean issuing all new orders to generals who were many miles in many directions. There was uncertainty of where Lee’s forces were in PA, and the belief was they would try to attack Washington from the NW, so it made sense not to advance too far north.

Reynolds clearly understood that Gettysburg had favorable terrain and ordered Oliver Howard’s corps to join him there, rather than fall back to Pipe Creek. After Reynolds was killed and Winfield Hancock arrived at Gettysburg, he confirmed Reynold’s decision to fight there rather than fall back. That was good enough for Meade, who abandoned the Pipe Creek line and moved up to Gettysburg.

It’s worth noting that a similar process was happening to Lee’s army. Buford had engaged Devin’s brigade (Hill’s corps), which was the vanguard of the Army of Northern Virginia. Lee had to quickly bring his three corps together at Gettysburg. Both he and Meade benefitted from the many, many roads that led to Gettysburg like the spokes of a wheel.

3

jrhooo t1_j1mj22p wrote

Important to note: at least in less movile eras, the vanguard could presictably be expected to encounter the enemy FIRST.

Even on a single fixed battlefield, thus their unit position in a battle formation, front of the group, right end of the group.

This was considered a very prestigious position for that reason.

In a fixed battle, the vanguard position would logically go to the “best” of your line units to strike the first blows.

But who that best unit would be could change. It could be decided by the leader of battle for that battle. There are plenty of examples of Viking or Celtic clans agreeing to fight together, but bitterly arguing over whose troops would have “the honor” of leading the formation. (To the point that there were even fights over the right to lead the following days actual fight)

On the other hand, some leaders might make a specific unit their vanguard unit, and continually maintain that unit as a vanguard.

To describe that in modern military terms, you could have 1st infantry, 2nd infantry, 3rd infantry, and you COULD select the best one of them at any given time to be your vanguard,

OR

You could say,

“We have an Army Ranger regiment. They’re going to take vanguard, because that’s what they’re for. We specifically select, train, and equip them that unit to be our vanguard unit. Thats why the get extra pay and special uniform markings and the prestige of being on the first-string-all-star team”

1