I've recently moved up from playing at Warlord level and using the advice on these forums I can now win confidently on Monarch. I've tried a couple of One City Challenges but lost badly both times. I do well through ancient and medieval era but it all goes wrong in the early modern period. In my most recent game I was well ahead on tech through most of the game and was first to Rifling/Nationalism/Steel. But then Tokugawa, who was on the other side of the continent, was out-teching me and he won a domination victory by vassaling most of the other AIs. My questions are: 1. How much war-mongering do you do in an OCC? 2. How do you keep your tech level up mid/late game?