I tried this strategy once at Noble and it's pretty effective
Tokugawa is my vassal and he was right next to me
He is weak and backward and only had rifleman while I had already finished researching all the techs
Peter was pissed at me for not paying tribute to him so he declared war
He landed lots of modern armour and other troops in Tokugawa land
Being far away on the other continent, I could buy some time by placing my mech infantries in Tokugawa's cities
I gave Tokugawa all the techs leading to mech infantries and gave him 1000 gold to upgrade his troops
I could afford it since I have finished researching everything and set my research to 0%
It seems like Tokugawa upgraded ALL his troops at a very cheap rate and I could leave him alone to protect himself
After I managed to defend Tokugawa successfully, I rushed for nukes and nuked each and every one of Peter's cities
Russia was turned into a nuclear wasteland

Tokugawa is my vassal and he was right next to me
He is weak and backward and only had rifleman while I had already finished researching all the techs
Peter was pissed at me for not paying tribute to him so he declared war
He landed lots of modern armour and other troops in Tokugawa land
Being far away on the other continent, I could buy some time by placing my mech infantries in Tokugawa's cities
I gave Tokugawa all the techs leading to mech infantries and gave him 1000 gold to upgrade his troops
I could afford it since I have finished researching everything and set my research to 0%
It seems like Tokugawa upgraded ALL his troops at a very cheap rate and I could leave him alone to protect himself

After I managed to defend Tokugawa successfully, I rushed for nukes and nuked each and every one of Peter's cities

Russia was turned into a nuclear wasteland

