Black Ice doctrines

[MasterBurte]

I'm playing as japan atm and was wondering how i can research the deep battle doctrine. I'm at war with russia early in 1936 and always get events that give bonus in blitzkrieg and deep battle. Sadly japan starts with grand battle doctrine. My army is going to be mainly SF so deep battle would fit well.

 

[Wraith11B]

This would be better to ask in the Black ICE forums.