A war chest is the required amount of PoE a flag must pay in order to declare a blockade on an island. The amount is based on the size of the island and the island's population (on Midnight only), if any.
- For outpost islands, the war chest is at least 25,000 PoE.
- For medium islands, the war chest is at least 75,000 PoE.
- For large islands, the war chest is at least 125,000 PoE.
If the defenders of a colonized island win the blockade, they receive 50% of the war chest. The PoE is placed directly into the fort or palace coffers. If multiple flags dropped a chest on the same island, the percentage is taken from the combined value of all the war chests.