When you look at the overall bonuses of the left tree of Mass Assault (Deep Battle) you see that the bonuses compared to the other trees are lackluster as far as organization, recovery rate, and attack and defense stats. The main benefit is all the supply reduction for a total of -30% which is huge. Therefore, Deep Battle is meant to be an unstoppable late game powerhouse. This is because it allows the player to fit more divisions in a supply zone than the enemy and with the added reinforcement rate bonuses the added divisions have a much higher chance to come in from reserves.
As far as division builds go I do the following. I make infantry 40W by using 25 infantry brigades. For support, I use engineer company, anti-tank (keeping it up to date us a must), logistics company, and signal company (if you have resources). This unit is overkill on defensive stats so the enemy has a hard time breaking through. It also has very high organization which is the most important stat in the game. With this high organization, your units will be able over time push the enemy units for all but the most fortified places. By late game with upgrade logistics company combined with Deep Battle bonuses you get -70% supply consumptions meaning you will always outnumber the enemy by a very large margin.
As for armor for Deep Battle, I also go 40W with ten medium tanks brigades and 10 motorized brigades. For support, I use same as infantry. These units are used to push the front where the enemy line is denser. For motor, I use 40W with 14 motor brigades and 4 rocket artillery brigades. These units are used the same as armor.
I use heavy armor for breaking fortifications. These are 20W and I don’t make that many. They consist of 5 heavy armor brigades, and 5 mechanized brigades, and with the same support as infantry.
With all this added together the way Deep Battle plays is different from other trees. You don’t have good breakthrough bonuses and move speed so encirclements are not the best. You don’t get huge bonuses for sitting around and planning. Deep Battle is designed for the player to push across a front and doesn’t stop so the enemy can’t recover. With the finisher from Deep Battle (Continuous Offensive) and the Offensive Doctrine field marshal trait, you get a massive -35% organization loss when moving. This is hard for any enemy to stop especially the later the game goes on. Be warned though, because the attack stats like soft attack, hard attack, and breakthrough are worse than the other trees you will take a lot of casualties compared to the enemy on a push across a front (especially against superior firepower). In the end, though you will triumph because it is all about who loses organization first regardless of manpower losses.
As for the right tree of Mass Assault (Mass Mobilization) is very situation. It is used if you are resource poor, but what you have is bodies to slow down the enemy which ANY country does with the bonuses for Mass Mobilization and mobilization laws. I find it works best with nothing but 10W infantry consisting of no support. This means the only thing being produced is guns. You can make defensive lines and fall backlines with bodies that will take the enemy a long time to chew through if they even can. Don’t worry when the -0.4 width kicks in from Human Wave Offensive. The new combat width of 8 still divides evenly with the battle combat widths of 80, 120, 160, 200 so you will incur no penalties.
I use Mass Mobilization for Italy which may surprise many people. This is because I build my industry which civilian factories and don’t want to trade for resources for the minuscule amount you start with for a major. I throw bodies at the allies if they attack me in Europe or Africa. Once the axis gets territory and pushes into the Soviet Union I ask for states with resources I need and when the resource problem is gone I switch to another doctrine (I usually build up a navy to compete with the British as top priority).
I hope this helps anyone who wants to play with Mass Assault. It is loads of fun!
