A simple corruption system to work along with a new citystate system!

City-states were one of the most interesting addictions of Civ5, along with others, and I'm glad they'll also be in Civ6 . But they don't influence (default)civilization as much as they get influenced by civilizations .

One idea to allow their influence to scale more is to implement a mechanic where city-states close to each other, that are not the "hostile" type, can form federations, usually at the start of the Medieval or the Renaissance era . Kinda like Switzerland, for example:

https://en.wikipedia.org/wiki/Switzerland

Federations are an evolution of city-states, but they are neither a city-state or a (default) civilization, but they can have some features of a civilization, some features of city-states, and some unique features . One of these features is to make federations work like a "bank", where players can "deposit" their money on them and where players can "borrow" money from them .

Then, you may ask: "What's the use in depositing money in federations and borrowing money from them?" . Borrowing money can provide several options that the players are free to choose, but there must be also bigger punishments for players that fail to payback . Or a better heuristic to add risks and rewards of borrowing is to place the rewards at the short term and the risks at the long term or to make the rewards small and predictable and the risks huge and unpredictable . And the punishments to declare war against federations to avoid paying for debts should be huge enough to make even the the most bat**** insane warmonger to never, ever, use war as a means to avoid paying debt.

But what about depositing? Depositing money on federations is one mechanic to aid players against corruption . Corruption should be a "hidden" and slightly unpredictable mechanic, which distorts your "gold" overview in such a way to decrese your gold input and to increase your gold expenditure, but these distortions will be hidden until you perform a "corruption checking" action or if your budget hits a deficit . You can deposit any amount of gold you want in federations, but if deposit too much, your "budget" will have a "deficit" and you'll have the usual penalties of deficit(strikes, decrese in the output of some buildings, units and wonders, etc.) .

Players can influence city-states to create a federation, and can send spies and armies to either fortify and stabilize the federation or to create dissention that will make the federation break . Federations should be the most fragile at the beginning, and the longer they exist, the harder it becomes to break them . If they survive 2 eras, it is no longer possible to break them.

From this basic template, a lot of other things can be added, to further expand the ideas mentioned here