Sandbox Ruleset
===============

History
-------

Sandbox ruleset started out as a copy of civ2civ3 ruleset as it stood in legacy Freeciv 2.6 (civ2civ3 is
Freeciv21's default ruleset starting from version 3.0).

The former ruleset for testing unusual features of the Freeciv21 engine was called 'Experimental' and based on
the classic ruleset that was the default ruleset earlier. As the default ruleset changed, we felt the need to
base also the testing ruleset to the new default.


Warning
-------

This ruleset is a playpen for demonstrating new features. There is no guarantee that games started with one
release will continue to be playable with another release (even a minor version), nor that the game will be
any fun to play. Nor are there guaranteed to be appropriate graphics for all the game elements in the supplied
tilesets, so substitutes may be used.


Main features relative to civ2civ3 ruleset
------------------------------------------

Nukes:

* The Nuclear has lost its Explode Nuclear In Place ability. It can still do Nuke Units and Nuke City.
* The new unit type ICBM has been added. It requires Fusion Power.
* ICBM can do Nuke Target Tile -- targeting any tile at the map no matter how distant.
* If ICBM upkeep cannot be paid, they explode in place.

Airlifting:

* Light weight units can be airlifted once Flight is known. Medium weight units can be airlifted once Advanced
  Flight is known. Heavy weight units can be airlifted once Fusion Power is known.
* To airlift heavy and medium weight units an Airport is required both in the source and in the destination
  city.
* Cities that know Flight can airlift one light weight unit per turn. An Airport allows a city to airlift one
  more unit per turn.

Map Stealing:

* Spies can steal other player's world map

Spy elimination:

* A Spy can eliminate non allied Spies and Diplomats out in the open without also trying to perform any other
  action.

Border Vision:

* Border Vision is gained mid-game once Electricity is known.

Destroy City:

* Leader unit can destroy domestic cities.

Unit Expulsion:

* Foreign units can be expelled from the territory of a player.

Paradropping:

* It is impossible for green Paratroopers to land on Forest and Jungle tiles. Veteran, hardened, and elite
  Paratroopers can still do it.

Unit Disbanding:

* A unit can be Disbandable, Undisbandable or ConsensusUndisbandable. The consensus among the player's
  bureaucracy is that ConsensusUndisbandable units never should be disbanded (or recycled). Under some
  governments it has the power to enforce its will.
* The unit types Battleship and Carrier are ConsensusUndisbandable. Both unit types gets an Easter Egg in
  their ruleset comments: a reference to a news paper article indicating that ConsensusUndisbandable is not a
  completely fictional concept.

Single Barbarian Nation:

* All barbarians belong to the same barbarian nation. There is no separate Pirates and (land) Barbarians.

Hermit's Place:

* Hermit's Places are spontaneously, during game, appearing bonus extras that can grant techs to units
  exploring them. See its Help entry under Terrains for more information.

Sea Units in port:

* Sea Units in cities defend with 1/4 of their usual defense value.

Goods:

* Trade routes can carry many kinds of goods. There is production chains like that city with Mine can trade
  Ore to a city that then can trade Metal to third city which can then trade Goods or Equipment to fourth
  city. Goods later in chains trade for higher value.

Corruption and World Size:

* Under Republic government, the speed corruption increases as one goes further from the capital is relative
  to the size of the world. At the maximum distance corruption is the same regardless of the size of the
  world.

Units can be bribed/sabotaged if not alone on their tile:

* Being part of a unit stack will not protect against spy actions.

Merchant movement restrictions:

* Caravans and Freight can only moves on roads and rivers (as in older versions of civ2civ3).

One-time trade bonuses:

* Caravans and Freight get one-time bonuses when establishing trade routes, and can get revenue even when a
  trade route exists ('Enter Marketplace'), as in older versions of civ2civ3. However, this latter action
  really requires a Marketplace building in the city.

Custom policy "Personal Freedom":

* You can trade off a science bonus against extra unhappiness from your aggressive military units.

Opponents not seeing units in fortress or airbase:

* Opponents cannot see units that are inside fortress or airbase. Units inside fort and airstrip can still be
  seen.

Buoys visible only once Radio known:

One can see Buoys only when one knows Radio. The leading player may build Buoys that others cannot yet see.

Stealing techs on city conquest:

* Getting a tech with city conquest is never guaranteed to give techs. In early game you have 50% chance to
  get tech from the player losing the city. After University is known, no techs are got from the city
  conquest.

Nationality conversion on conquest:

* When a city is conquered, 25% of its inhabitants convert to the nationality of the conqueror.

Combat Rounds:

* Each combat lasts 15 rounds at max, even if neither side dies in that time.

Caravel needs supplies:

* Caravel needs to spend at least every third turn change next to a land tile to load supplies for the crew.
  Otherwise the unit is lost.

Multiresearch enabled:

* When switching research, already accumulated bulbs are not transferred to the new technology but are
  remembered towards previous research.

Tech trading requirement:

* Treaties cannot have tech clauses before both sides know Writing.

Plague:

* Double probability for a plague spreading along a trade route. Enemy spies can release plague samples found
  in a target city's Research Lab.

Disrupt Supply Lines:

* Some units can disrupt the supply lines of enemy units. This removes 1 MP from the target unit at the cost
  of one move fragment for the unit doing the disrupting.

Casus belli:

* Staring to do Pillage to a tile gives the tile owner (not the extra owner) a casus belli against you.
