1350 AD
Wow, those Cho-Ko-Nu's are POWERFUL! I will share some game details:
War Machine
I went with an all out Cho-Ko-Nu and Treb war. As suggested by
Sun Tzu Wu, I used Great Scientists to bulb Machinery, Engineering and Astronomy. I waged some serious Cho-Ko-Nu war! I used only Cho-Ko-Nu's and Trebs the whole game with a few Pikes and Elephants for defense. Below is a "collage" screenshot from the statistics screen(s) showing pertinent units:
Map
I started with a two golds, corn, pigs, 4 FP and a lot forests (and more grew). I had decent food, many commerce resources, horses and copper in my REX zone. Unfortunately, no Iron. I made an impromptu war with a few chariots and axes to get my iron from Alexander:
I rolled him first, then Hammurabi, Charlemagne, Cyrus, and Pacal on my hemisphere. Then I killed Julius Caesar and Sury on the other hemisphere.
Research
I went for worker techs, writing, mathematics, metal casting. I traded for iron and alphabet. I researched aesthetic and then bulbed Machinery, traded for construction, bulbed engineering and it was all over. Well... not really. I should have researched currency early so I could build wealth. I had no research for a while. I researched CoL to get courthouses up across my empire in about 3 turns. I got the AI to trade me fishing, sailing and calender once I got Machinery and Engineering. I then researched currency, then compass and optics. I was on optics a long time at 0% research due to economy. I bulbed Astronomy (about 1/2 the beakers) once I got optics. I got several other techs not taking one last, weak city of the larger opponents by agreeing to peace for techs. Then I killed them off after 10 turns of peace. This was good for tech backfill.
Civics
I used two: Slavery and Vassalage. I got monarchy so late that it didn't matter. I was really harsh with whipping and only kept one unit garrisons, so HR would not have helped much. No CS--whip, whip, whip!
Tips:
1. Take settlers with to the other hemisphere and raze the larger cities and put down a new city to avoid city resistance turns.
2. Once you get Astro, put your commerce toward spy points against overseas AI for city revolts. Those 100% cultural defenses suck!
3. Sue for peace to pick up techs when the AI has one city left. There are no vassals, so there is no harm.
4. Use accuracy upgrade for trebs. Settle first GG and build only trebs in that city for 5XP needed for accuracy. Let your Cho-Ko-Nu's do the collateral damage.
My final screenshot: