Heres a tip. Try to defend mother russia at the first riverline not the border. The border is marshy. The River (I forget its name!) you can pretty much build 2 forts on it and have 12 infantry up there its very hard to dislodge them. The only easy was up is smolensnk, just stack em up right there. Keep about 30 armor spread out in reserve behind the forts to move on and contain breaches the moment they happen.
Bonus: your counterattack in the south could of beat me. You did break my troops for a bit and had them reeling. If you had drove north you may have did some great damage to me. But you paused in front of some reorganizing units.
When you originally declared war 58 of my best divisions were preparing to invade Romania and turkey and then from those 2 countries, you. Wether you knew this or not I dont know. But they were nowhere near poland so I had to fight through poland with only 30 or so divisions with worse off gear, would of been just enough to take out polish army. Not the Soviets Plus I had to keep 22 men on the siegfriend (with 6 tanks to counterattack) That you declared war on me, this was a suprise, that you would DOW on me and not poland to fight in a narrower corridor was strange.