RESOURCES : Stockpile & Transfer Spoiler First new city, first transfer link... : Transfer are automatically made between cities of the same civilization if there is a river route (as in the above picture), a road, a sea route, or a trader linking them. The routes have different efficiency, limiting the amount that can be transferred, using a trader will allow 100% efficiency. International transfer will not be automatic, unless a specific trade agreement is made, or simply when using a trader unit. Spoiler And first transfer the following turn : As when transferring to units, cities keep a percentage of their stock to themselves (more important for city transfer : 75%), and will transfer only to a city that as less quantity of a resource. In the above case 45 is the reserve value of the stock of sheep in Cairo, the surplus (6 sheeps) has been send to Damietta. There is no migration of population coded yet, but it's planned, at least for later eras.