Doctrine research

[paranoidsteve]

I know that with land doctrines you may only train one of the 3 tree options . Does the same apply to the air and naval doctrine trees, or can you train the lot?

 

[Zankoas]

Same applies, you pick one and only one

 

[paranoidsteve]

Same applies, you pick one and only one

Source?

 

[Zankoas]

WWW, sadly can't remember which one...

Though the wiki says so as well, it also doesn't give a sourceas well, sorry
(http://www.hoi4wiki.com/Research)

 

[Prusenoff]

Naval Doctrines
Secondly, we have the naval doctrines. There are three separate doctrine trees, and you can only have one researched at a time.

I can't find anything on air doctrine,but i suspect the same applies there as well.

 

[LordOfWar16]

I know that with land doctrines you may only train one of the 3 tree options . Does the same apply to the air and naval doctrine trees, or can you train the lot?

you can only pick one of each trees. With that said, it should be noted that each tree will share some common doctrines that the other trees also got, just at a different position. You can of course, just as with the land doctrine tree aswell, switch to another tree, which will set you back in your progress tho, so it comes at a cost. Germany for example isnt limited to the blitzkrieg land doctrine or trade interdiction naval one.

yeah, there are several techs that exist in several doctrines but they are unlocked at different times. For example Floating Airfield tech is fairly early in base strikes doctrine and endgame techs in Fleet in Being and Trade interdiction.

As you can see the trees share some (not all) doctrines, just at a different position down the branches.