I. First things first, Disclaimers: 1) I typed this guide Jan 14th, 2021, originaly on Old World Discord (come join us, we love you already) so the game is still in Early Access and mutating fast. Some or all of this will become obsolete as the game evolves. I hope some of it will still be interesting in a few months, but if you're reading this later, some of the game mechanics explanations might not be accurate anymore. 2) Outside of GOTW I only play at "The Great" these days. Some or most of what I will describe will probably only be relevant for high dificulty settings. 3) At "The Great" and at the time of typing this guide, I can only describe one path and strategy that should work more or less reliably. I have other ideas but I have yet to prove that they work. Many players have done OCC before me ofc, and I expect they will have other ideas, advices, other strats, etc. I'm just documenting the one I found . This is the Path of the Sage Builder. II. Second things errr, second, Warnings: The "Challenge" part in "One-City Challenge" is not an exageration. I'm not sure if the challenge introduces as much of a gap in the dfficulty on easier settings, but at The Great at least, the AI won't pull its punches. Cyrus won't care that you want to try a fun challenge, misled by a forum post. Romulus will see your promised great city of wonders as a mere bump in his own conquests at best, as a prize to grab otherwise. Diplomacy won't be optional. Late game, you will be able to hold your own against anyone... the challenge is getting there. Early game, you will probably have to bow to some extortion from the AI. When Ashurbanipal comes pay you a vist in the shower, you will politely pick up the soap as he asks you. Political marriage will be a thing. For me the difficulty felt like it was at least two notches harder than a standard game. Like my first "The Great" game, I needed a few map restarts, no quite legit undos, RNG hacking, "reload and rethink", and a generaly unhealthy amounts of scumming. I don't claim to be some kind of OW expert but I'm normally quite confident playing huge maps at this difficulty level. Here I ressorted to trickery that would shame my gamer son if he knew what I was up to. This said, I think I now understand this strategy better and can replicate it less dishonorably. If your first attempt at OCC is at the highest level of difficulty you usually play at, be prepared for some scumming or, well, defeat: chose your shameful display. You might want to go 2 or 3 levels below usual to have a more relaxed and honest experience. I'd rather cheat my first game, cheat "just a bit" for my second victory, play honestly for the third and get better that way but that's down to taste and how much grinding you can tolerate. There are a lot of tricks in there that are relevant to any games, but if you're just starting it will probably make more sense once you've had a few games. I wouldn't recommend trying OCC before completing a few more standard games. III. What you need: - A strong starting location. Feel free to try it with a no-growth start or without marble, I'm not stopping you. I used the Coastal Rain Basin for my attempts. This tend to produce fertile maps, but any script will do so long as you get a strong start. Strong start means marble and growth resources in reach. - Egypt. I'll explain why later on but the only strategy I'm confident with at the moment simply requires Builder leaders, at least for the early/mid game. - More precisely, you will found with the sage family, the Thutmosids. - Willingness to restart/redo things. Either Hatshepsut will have to live very long, or you need your heirs to be Builders too. Nothing else will do for quite some time. If you don't have a candidate heir builder and you die, reload, undo scum, or start a new game. Let's call it the Path of the Sage Builder Strategy. Why should that more or less work ? So, obviously in OCC you only have one city. Everything is slower. If your city produces something you need in 2 turns instead of 4, you've doubled the output of your empire. If you go from 2 turns to 1, doubled again. Very simple, but it means you want to 1-turn everything you can as soon as possible. Consequence no 1 : if you can't speed up improvements building, then if you want a Citadel, you will probably need 15 turns. 5 for the Garison, then Stronghold, then Citadel. Sure you can be a bit faster with Guilds, but Guilds is at the other end of history. IV. Builders ! The only way to truelly speed improvements up is to have a Builder leader. Who starts with a Builder Leader ? Egypt. Their characters also have a bias toward builders, so you should be able to generate Builder heirs through commerce or philosophy studies. You will want 5, prefferably 6 workers as soon as possible. Rural improvements are 3 turns on flatland, Urban improvement 5. So 6 workers is 2 rural improvements each year, or a full urban one plus something, or a full urban one on a hill. You will also want plenty of wonders and you will not want to wait 10 or 16 turns for them to complete and start paying off the investment. You know what ? Builder leaders train workers twice as fast, and that's the second reason why Builder is always nice but so much stronger than anyone else in OCC. That's not all. When your leader is a builder, you can, in 1 turn just like a road, for 10 stones (20 on a hill) just like a road, build a Urban tile. No improvement on it, same restrictions as for any urban improvement: needs to be adjacent to 2 other urban tiles, or only one coastal urban tile if coastal itself. But just as urban improvements, they grab the surrounding tiles. Territory will be extremely valuable for a variety of reasons, but if you only think of the resources you'll need every year to build and train everything you'll need, that's reason enough. A lake or a coast nearby is very valuable just because of that, it will allow you to grab a lot of space very quickly. The extra stone cost is so worth it it's negligible. In your land expansion plan, all urban improvements that don't require the normal adjacency are extra valuable, as they allow you to start a urban region in the middle of nowhere. Hamlets, wonders, monasteries, all are extra precious and their placement can be extremely impacting. So you want Builder leaders. If your first born turns out tactician, well, tacticians are just great but in OCC you'll desherit the poor child in favor of his younger builder sibbling. Yes, even if he's an idiot. So, to 1-turn improvements, build wonders in a few or a single turn, etc, you want Builders leaders. Now, you will want to 1-turn other stuff. You will want to 1-turn tech if possible, you will want to 1-turn projects, 1-turn units, 1-turn everything. Most importantly, the best way to generate anything of value in OW are specialists. You want training for military, growth for your fat city, science... The most effective way to generate all that is specialists. You will need lots of Elder specialists. So, to unlock "1-turning stuff", the first thing you need to 1-turn is specialist training, and that takes civics. Comfortable, vast, huge, unreasonable quantities of civics. High Charisma is nice, but to make the most of it you need governors. The only other boost to civics generations at the start of the game are marble quaries and stonecutters. Also, Sage families have a 25% lower civics cost on urban specialists, which is the main reason we want to play a Sage Family. Luckily, Egypt got us covered, we will play the Thutmosids. The ability to conduct inquiries for science (same same, you want to 1-turn inquiries as soon as possible) is also quite important, but the killer is the faster urban specialists. Faster rural specialists (Landowners, -50%, also available to Egypt) could also work as it'll speed up the very begining, but overall since we'll upgrade urban specialists we'll train wayyyy more of these guys. The science per citizen is almost irrelevant, as for the most critical part of the game you'll have very few or no citizens. Crazy amounts of specialists, though. So, to 1-turn stuff you'll need first to 1-turn specialists, and for that you will want some marble close by (criteria for a strong start) and to found either Sages or maybe Landowners (Didn't try and you can't make inquiries. Something to explore but I wouldn't recommend it if it's your first OCC). Some sort of coast (lakes are excelent) nearby for rapid urban expansion are great.