Part 2 - "The Infantry Fortress"
The Infantry fortress is used when no enemy cavalry is present. It is only used for fighting infantry.
The Infantry Fortress grew out of the cavalry Fortress, although it wasn't quite the bullseye at first that the cavalry Fortress was, it took some experimentation for me to find the right combinations to make it work. Cavalry has only one mode of attack, the charge. Stop the charge, and you stop the cavalry. Squares stop the charge, and so stop the cavalry. Simple, and so the Cavalry Fortress was also a simple, static formation.
Infantry is different, primarily because it has more modes of attack. While cavalry can only charge, infantry can both charge and shoot. With the enemy having more options, the fortress must become more flexible. Therefore, the infantry Fortress is not the static formation that the cavalry fortress is. The principle of it though is the same, to be able to bring your artillery within canister range and be able to protect it so it can keep inflicting maximum casualties.
The infantry fortress is quicker and easier to put together than the cavalry fortress, both because you can make use of stock formations from the Grog toolbar(as opposed to the cavalry fortress which must be put together by hand, one unit at a time) and because precision of unit placement is nowhere near as critical as it is with the cavalry fortress.
It can begin with a simple stock infantry brigade formation like "Line" or "Double Line". Even "Line with reserves" will work fine. This is just an outline anyway. Lets assume we are working with an infantry brigade of 5 battalions. Pull one of the battalions off the front line to open up a field of fire for the guns, and then wheel the artillery up and place them in the space left behind by the unit you withdrew.
You should end up with an infantry battalion on the left, deployed in line, the artillery in the center also in line, and another infantry battalion on the right in line as well. The Infantry line should be setup even with or a little ahead of the guns once the guns unlimber, so initially place the artillery a bit back from the infantry. Something like this: --------_________-------- When the guns unlimber they should be about even with the infantry. The two infantry battalions in this forward position should be the two units in the brigade that have the highest troop quality in the brigade.
You don't need to squeeze in on an 8 gun battery the way you do with the cavalry fortress. Just deploy the guns at full spread and extend the infantry on either side.
That leave us with 3 battalions left to position. Of the 3 remaining battalions take the two with the highest number of men and deploy them in assault column directly behind the frontal infantry battalions that are in line, both the left and right frontal units. This is your counter attacking force. Should an enemy infantry unit charge one of your frontline units and force them back, you can immediately counter attack them with the rear units before the enemy unit has a chance to reform and charge the guns.
(These units are sometimes optional, depending upon the size of the brigade you are working with. For instance, if you are working with only a 3 battalion brigade, the assault column reserve is the least critical part of the formation, and the one you would do without when working with a smaller brigade.)
The final battalion is your source of skirmishers. I generally deploy them in line behind the artillery, kind of right behind the battery commander in a more or less central position. From this battalion you want to split off four 100 man skirmisher units. One each to be placed in front of the two frontal line battalions, one to cover the left side of the battery, and one to cover the right side of the battery(if using a 6 gun battery you can probably get away with just one skirmisher unit to cover the whole battery) These skirmisher units should all be deployed about 15 to 20 yards ahead of the infantry battalions and the artillery battery. Far enough ahead that the skirmishers are effective screening the battalions and the battery, but not so far ahead that they force the enemy to stop and engage them while still to far away to come within canister range of your battery. Remember that's the whole point of this, canister, blazing away as fast and as regularly as possible.
This is basically a game of you having all the options and abilities that the AI has at its disposal, but you are always one arm ahead, because you have the guns at close range, and they don't.
If the enemy comes forward with skirmishers, they will engage your skirmishers. Skirmishers vs skirmishers is generally an even fight as far as a shooting match is concerned. But its not an even fight here because the enemy skirmishers are not only dealing with your skirmishers, but also dealing with being pelted with canister fire from your guns. They will not stand for long.
If the enemy line infantry advances, they will do one of two things. They will either stop and engage your skirmishers in a fire fight, or charge the skirmishers.
If they stop and try to shoot it out, they've already signed their own death warrant. The skirmishers will get the better of it in a fire fight with line infantry as it is, and the canister will rip huge holes in the enemy lines as well. They will soon run off as well.
If the enemy infantry tries to charge your skirmishers you have two options:
1. Even if TC'd skirmisher units will not engage in a melee, they will retreat instantly. As soon as you see the enemy getting ready to charge the skirmishers, form your line units directly behind them in assault column. When the enemy attempts to charge the skirmishers, the skirmishers will retreat and the enemy unit will stop to reform. While they are reforming they are vulnerable. Counter charge them with the unit you just formed in assault column and drive them off. Your artillery will probably give them some canister shots as they withdraw as parting gifts, thanks for coming, please come again.
2. You can recall the skirmishers right before the enemy charge comes in contact with them.(This is cheap, damn cheap, in fact its practically cheating) When you recall a skirmisher unit as far as the game is concerned, they instantly become part of their parent unit again(even though their sprites are still present), their unit flag vanishes and they are no longer considered valid targets on the field.
Doing this has a number of advantages:
First, it stops the skirmishers from taking any casualties at all from being charged.
Second, it still forces the enemy unit to halt their charge and reform because they have lost their target. You can then counter charge them with your infantry while they are reforming exactly the same way I described above.
Third, it saves you the trouble of having to bring the skirmishers back up to the front after having retreated, which can sometimes be very far to the rear, and they use up a lot of their fatigue by running that far. Instead you simply kick out a fresh skirmisher unit from your skirmisher source battalion deployed behind the guns.
And finally, by doing this you are constantly cycling in fresh skirmisher units with full ammo and recalling more expended skirmisher units. Because all the skirmishers are coming in and out of the same unit(the one deployed behind the artillery), this one unit becomes a never ending source of fresh skirmisher units.
At any rate, once the enemy has withdrawn, DO NOT PURSUE THEM. All that will do is lure you away from your guns and force you to engage the enemy under less advantageous circumstances, possibly even within range of the enemy cannon, a most certain No No. Reform the Fortress, bring the skirmishers up again and wait for the enemy to come back for more fun. Rinse and repeat.
Some video examples of the infantry fortress in action include:
Episode 12: "The King of Westphalia" beginning around 23:38
https://www.youtube.com/watch?v=kHG7Y6M2K5U&t=2386s
Episode 22: Ligny: "St. Armand" starting around 1:22:42
https://www.youtube.com/watch?v=zBpxQjDmuuo&t=5021s
Episode 24: "Count D'Erlon's Attack" starting around 29:00
https://www.youtube.com/watch?v=ZI7m-VsTlAw&t=1745s