> For the complete documentation index, see [llms.txt](https://cryptopolium.gitbook.io/whitepaper/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://cryptopolium.gitbook.io/whitepaper/marketplace/how-it-works.md). # How it works In the marketplace, the player can exchange trading posts with his opponent, but there are some conditions to be fulfilled beforehand. * [ ] All trading posts must be sold. * [ ] One of the player has to be visiting the Marketplace. * [ ] The trading posts to be traded cannot be part of an already completed province. {% hint style="warning" %} IMPORTANT! The player who swaps a lower-value post has to pay five times the difference. {% endhint %}