With the culture trajectory firmly set, now research took center stage.
Beginning a little while before the Porcelain Tower would complete, I shifted all of my spending from city-states to research agreements. I already had all non-hostile maritime CS. I had a couple cultured CS, but the rest could wait until the industrial age when the bonus would ratchet up. Six Research Agreements came in the first wave, concluding between turns 144 and 154. The second wave ramped up to a full boat of 9 RAs with every possible AI partner, and these cashed in between turns 176 and 198. These rocketed me through the Renaissance quickly, as research agreements always do.
One trick I pulled was to loan cash to the AIs in return for per-turn payments, in order to give them enough lump sum to sign an RA. In this way I essentially used AI GPT to pay for the research agreements. And all along I continually sold luxuries and resources to the AIs, as is standard Civ 5 strategy.
I also played tricks to manipulate the median tech value to get maximum payoff from each RA. It really didn't matter what order I got the techs; as always in Civ 5, tech was running far ahead of what the cities could build. In this shot, I have the median pushed into the Navigation column, so each research agreement would complete more than one entire cheaper tech in filling in Banking - Machinery - Printing Press. I went to Chemistry early as usual for the tile yield bonus, but then left Fertilizer unresearched since it's such a great position to pull the median tech value upwards.
The Taj Mahal completed here on turn 175, and I chained Golden Ages all the way from Taj Mahal through the end of the game. Taj was followed up by three Great People firing for Golden Ages; my original Great General, the GG from Brandenburg Gate, and a late Great Artist that spawned late enough that it couldn't save any turns towards the last policy. Endless Golden Ages means tons of money, of course, and now I completed buying every maritime and cultured city-state on the map.
I'm not talking much about city management here, but there wasn't much to say. They built all the usual stuff, culture buildings and aqueducts and workshops and markets. Growth leveled off around size 23-25, since there wasn't enough time left for food surplus to turn into a usefully productive citizen. National wonders came eventually. Sparta worked maximum artists at all times, since it had the National Epic and all of the artist GPP wonders. Each other city worked maximum artist specialists once the Freedom food reducer policy was adopted. Athens reached 500 culture/turn, the standard number for a capital working a dozen landmarks.
Getting back to Research Agreements, the culture victory is very well served by the structure of the tech tree here. The wide fan-out from Electricity means that you can get the median into the Refrigeration column right away. And the tech goals for culture just happen to run through Electricity, at Telegraph and Mass Media. The entire bottom line can and should be blocked by avoiding Metallurgy; you don't need any of the military stuff there, cannons and cavalry are well good enough for defense. My second wave of RAs reached just far enough to complete Telegraph, Radio, and Mass Media. Refrigeration was researched normally.
That meant Sydney Opera House, but the problem was that Athens spending all its laborers on landmarks and artist specialists didn't have much hammer power to build it. Fortunately, Liberty was completing right around this time, so I took a Great Engineer to rush SOH.
I took Penicillin and Plastics with two final Research Agreements, carefully NOT completing the first one with the first RA, in order to keep the median in that column for the second RA. (The available techs are Metallurgy - Rep Parts - Penicillin - Plastics - Electronics. The median is Penicillin as the 3rd tech of 5. Researching Penicillin would drop the median to halfway between Rep Parts and Plastics, which are the 2nd and 3rd of 4 available techs. Let the first RA credit towards Penicillin but avoid completing it, and the second RA awards its median value in this column too.) Then I built Oxford University to take Ecology. The point of all this was to buy both Hydro and Solar Plants in Sparta for maximum speed on the Utopia Project.
200 production per turn.
The last policy hit on turn 225. Utopia Project took just 7 turns to build, cutting a turn by chopping Sparta's forests on the last turn.
Culture Victory on turn 232, 1610 AD. I think that is pretty fast indeed. The CFC HOF shows a few faster results, some dipping into the 15th century AD, but I'm satisfied with that one.