Bagpuss
Chieftain
I've worked out that a very sudden rise in AI power is usually associated with them doing a mass unit upgrade when it becomes available. This kind of spike is usually over in a turn or two though. When you see a sudden, sharp rise in AI power over the course of 10 turns or so can this be a reliable indicator that the AI is seriously preparing to go to war? I'm getting nervous that the Japanese are tired of watching me out-tech them in my current game. Time to build machine-guns?