Huh??? About the turns. It takes Germany 3 turns to get to Kar, 4 to get to Mos and vice versa for Russia. And with the UK navy in the UK sz it takes them 3 to get to Kar as well. Turn length has nothing to do with strength of country.
Japan and the US are strong precisely because they are isolated and their Capitals are never in threat of being taken. After Turn 2 Japan has minimum 34 IPC and one focus - get to Moscow! While the US will have 32 IPC and its 6 trannies and one focus - get Germany!
It is very easy to mount an offensive with both Japan and the US. One focus, get infantry to your front.
Japan - turn 1 buy trns, inf. Turn 2 buy trans, inf. Turn 3 buy trans and inf. Turn 4 buy inf. Turn 5 etc…
You have a massive economic machine flowing.
US - turn 1 buy trns, inf. Turn 2 buy trans inf while setting up the train from US to Canada. Turn 3 buy trans and inf. Turn 4 buy inf. Turn 5 etc…
The train is set up and now every turn you have 10-12 inf going to Europe.
Again, you have the economic machine of the US flowing.
The question was which is the strongest country, not which country starts out the strongest.
I think you have your numbers backward for Germany and Japan. Say 42 IPC - 14 inf. Germany must divide the 14 between Afr, WE, EE Whereas Japan can throw 14 inf right at Russia. Japan is stronger that way. Germany is the one that needs the 60.
Japan can get away with far less IPCs than Germany. Germany just has too many fronts to cover to be the game dominator. As does Russia, and the UK needs too much help to be considered a singular powerhouse.