Thanks for a fun game! I do admit, though, that there was some ambiguity that left me guessing--for capturing land (aka a City) from an AI who had to survive, what qualified? Assuming that we want to capture land from AI 1:
1. Could we capture a City from AI 1 that had originally belonged to AI 2 and which AI 1 had captured from AI 2? I.e. We'd take a City from AI 1, but it wasn't a City that AI 1 had settled.
Yes. New Amsterdam captured by England then by Colonies.
2. Could we capture a City from AI 2 that had originally belonged to AI 1 and which AI 2 had captured from AI 1? I.e. We'd take a City that had originally been settled by AI 1 without ever having to go to war with AI 1.
I would have to accept it. Meets letter of the challenge but doesn't not fulfill implied spirit of requirement to go to war.
3. Could we Culture Flip a City from AI 1? I.e. No war with AI 1 needed.
I would have to accept it. Meets letter of the challenge but doesn't not fulfill implied spirit of requirement to go to war.
4. Could we Culture Flip a City from AI 2 that had originally belonged to AI 1 and which AI 2 had captured from AI 1? I.e. No war with AI 1 needed and not directly taking a City from AI 1.
Doesn't count as taking a city from A1.
5. Could we gift a City to AI 1 and recapture it? I.e. War needed, but potentially an easy conquest.
Nah, you are just getting your land back, not taking theirs.
6. Could we gift a City to AI 1 and then Demand it back in tribute? I.e. No war needed, just a large enough army to back up our threat.
Nah, you are just getting your land back, not taking theirs.
In the end, I dispensed with potential ambiguity and make sure that I militaristically took at least one City that was settled by AI 1 and owned by AI 1 at the time of capture.
That's the spirit!
However, these kinds of questions are good to keep in mind for future such challenges, with the answers being either specific or else sufficiently intentionally vague so as to allow for multiple ways of completing said challenges.