Part I : Presentation
So I decided to make a Let's Play / After Action Report about Rise of Prussia, a game that should cater to most of the traditionnal Paradox crowd : it is not full of flashy animations (it doesn’t have any actually), but it is a complex game where patience and planning is necessary. No instant gratification, just bad news stacking on more bad news. It is unfortunately fairly unknown – even though it is relatively accessible for a wargame.
The AI of the game is outstanding, but I am going to do a PBEM [Play-by-email]. The other player may not post here, but rest assured he will play as meanly as he can.
Rise of Prussia is a Simultaneous Turn Based game. I play my turn, my opponent plays his - and then both actions are resolved at the same time. A "turn" lasts 15 days.
This AAR is intended for beginners, so I will explain game concepts from time to time, as the need arises.
I will play the 1757 Grand Campaign (longest game possible), with Historical Attrition, Historical Stats for Leaders, No redeployment, Normal Activation Rules, Long Delayed Commitment in Battle, so in one word, as realistic as possible.

I will take Prussia and its coalition, my opponent will take Austria and its coalition (there are only 2 players : each player is playing all the countries involved in each coalition – which does not mean that “nationalities” of units have no impact – far from it). It is quite fitting, because having played 3 games against that opponent (2 at Birth of America, 1 at Revolution Under Siege), I know he is a master of defense, but too careful and slow in attack - which is pretty historical for the Austrians. I believe I am a more balanced player, even though not quite as aggressive as the real Frederick was.
Anyway, what is the situation in 1757 ? Well, see by yourself here (explanations to follow).

Long story short : during the First Silesian War (1740-1742), Frederick used the fact that Austria had its hands full in the War of Austrian Succession to quickly seize Silesia, uniting the two parts of his Kingdom, then peaced out of the war – the War of Austrian Succession would last until 1748. This angered both its enemy (Austria) and its allies (France and Russia).
In 1757, Austria is building an alliance to take Silesia back from Prussia. Prussia has not a chance against a Austria-Saxony-Russian-French-Swedish coalition. But Frederick has a plan : if he strikes fast and hard, he can kick Saxony and even Austria out of the war. Without Austria, France and Russia would have no reason to carry on fighting, and Sweden is not strong enough on its own. Thus started the 7 years war, with a massive offensive on Saxony, to destroy it before it mobilizes. Saxony is annihilated, its cities seized, and the moderately big army it could assemble is sieged at the Pirna Camp.
Which is exactly when the campaign starts.

[The assault on Saxony itself is a “tutorial” campaign]