The game has one principle supply network method used for transporting supplies on land and overseas:
# All units draw supply by requesting it from the province they are located in.
# Each province starting from the unit's location leading back to the supply stockpile it is listed as being "supplied from" will request supplies from the province next in line never
deviating more than 90degrees from a path towards the stockpile unless sea zones force a deviation. # If the next province in line doesn't have any supply in it to transfer the province will show as red, if the province does not have fuel it will show yellow. If it has supply but not enough to meet the needs it will be brown. Green with red hatchmarks is supply throughput maxed provinces is land that is at its max throughput.
# Every request to a province for supply includes a supply transfer cost that can be effected by revoltrisk if the land is occupied/annexed.
# If one adjacent province cannot meet the total supply need, multiple adjacent provinces may be used but never beyond a 90 degree arc in the direction of a stockpile.
# Each province between the requestor and a supply source will carry the request for supplies forward, aggregating other supply requests as appropriate.
# Supply moves one province per day.
Very often the supply units are recieving never came from a stockpile. Ports recieve fresh supply each day in most cases for a landmass and every day if supply production is on, IC provinces in the region recieve supply as well that can be injected into the supply lines to help with long supply lines.
## Supply missions can be used to siphon supply out of a large stockpile towards the front faster and more efficiently than land in low infrastructure regions.
# '''Convoys:''' AI control of convoy creation and destruction can be turned off, allowing a player to manually create convoys.
## If a landmass stockpile is beyond a certain value convoys will stop shipping supply till the stockpile drops down to a level where it needs supply again.
## Stockpile thresholds are a calculated equation based on the demand of the stockpile province on any given day multiplied by a certain amount of days, generally any stockpile over 40k stockpiled will not allow for convoys to ship supply till it drops below that. This value could be higher if the landmass has a great many units on it.
# '''Supply re-route:''' Starting in Semper Fi, it is possible to create sea convoys to improve the supply flow to areas already connected via land to the supply depot (Lenningrad and Vladivostock: in addition to a land connection, can also have a sea connection). This can happen so long as the provinces involved are separated by at least 10 provinces.
=== Supply Map ===
The supply map effectively shows
that the supply network is not a static network, but instead a constantly changing network based on unit needs. ''Thus, this map mode is a snap shot in time, not a comprehensive view of what your supply network might be capable of in different circumstances.''
* Green shows it is receiving all of its requested supplies and every unit is in supply.
* Blue shows a supply surplus.
* Black shows zero supply,
zero requests* Brown shows province has a supply deficit: demand is higher than throughput. Effected by infrastructure level, terrain, or tech level.* Red hatching shows limitation being imposed on the infrastructure.* Red shows the province 's local supply value is 0.
For more details, view this post [http://forum.paradoxplaza.com/forum/showthread.php?p=10011660#post10011660 by potski] on the HOI3 forums explaining the supply map and many intricacies and implications of supply draw.
=== Allies & Puppets ===
When units are in an allied nation, supplies will be drawn from the allied supply network. Meanwhile, an automatic and invisible trade route will be created between the two nations, where the exact amount of supplies and fuel will be sent from the nation with its troops abroad to the allied nation hosting those troops. Some minor allies and most puppets will relinquish control of supply in the region to their master nation or a major nation with better doctrine/techs for supply. Example: Manchukuo will never retain a stockpile in its capital and will always be supplied from japan's port stockpile in asia. They will constantly produce double daily supply because their supply system is basing its values off an empty capital province.
There are several factors that limit the distribution of supplies: