Printer
Printer is arguably the most important thing to understand in multiplayer, arguably more so than your tech or industry as you can punch far above your weight if you understand force multiplying by attacking key parts of the enemy front line and even simply checking enemies far larger than yourself by shaping yourself correctly. This entire section is to help you understand the entire micro game so you can better understand macro strategies and even begin to write some interesting plays for yourself.

Example 1: Lets us take a look at the typical Alsace-Lorraine border between France and Germany and for the time being labeling their fronts with colored lines: France (green) to Germany (red) in the picture. https://i.imgur.com/PCQPceT.jpg

Lets say the situation is France is invading Germany to take rhineland for whatever reason, so France is the offensive party and Germany the defensive. France will most likely take the opportunity to attack, and ideally, attack into a plains province to minimize terrain bonuses that Germany may have in the southern forests.

This gives France 3 avenues of attack as picture: https://i.imgur.com/tt13J65.jpg

From this situation you can see that Germany has 2 level 3 forts to the north and a single level 1 fort to east. More often than not, an inexperienced player will decide to attack the level 1 fort. This a massive mistake as I show in the picture: https://i.imgur.com/JfgS8iJ.jpg

France attacks the level 1 fort and is cut off by a counter attack behind its offensive and this leaves the French printer in disarray as France cannot effectively reinforce the ongoing offensive in Germany is now forced to attempt a breakthrough to reach those troops, or alternatively, retreating those troops back into the offensive Germany started. The point of this is that in a defensive war, Germany has with a single move removed initiative from France and thrown her into a reactive posture.

Example 2: Lets look at another example of printer interaction: https://i.imgur.com/OIP09fM.jpg

In this example, the printer is far more complicated with rather glaring threats for either side as can be seen by the picture: https://i.imgur.com/djLDOvB.jpg

The Point of Printer: If you haven't noticed already, the most important element of a particular province in a printer is how many neighboring provinces are friendly and how many are enemy. In the first example, France began an offensive into a province with a HUGE printer disadvantage because the defending German province had 5 neighboring provinces that could effectively reinforce the battle while France had only 1 to reinforce the battle from, and that 1 was at risk of being attacked.

In the second example, see if you can count the advantage of each province based on how many neighboring provinces can directly reinforce into it and if those reinforcing provinces can even be attacked to "check" their reinforcement capability into the primary attack point! I'll re-link the picture here for your convenience. https://i.imgur.com/djLDOvB.jpg

What I want you to derive from this is that a "good printer" is a printer that is full of entirely advantageous provinces with reinforcement lines that cannot be interrupted and gives you a good position to interrupt your opponents printers. This is absolutely the most important part of understanding Victoria 2 micro and to make split second decisions on where you must attack and where you must defend and the importance of a particular province in the context of the entire war.