[freeciv-ai] Re: Document for newbie against the AI

[Jordi Negrevernis i Font <jorneg@xxxxxxxxxxx>]

En/na Thomas Strub ha escrit:

> I doubt that the "How_to_beat_the_AI.html" will give good players. And i
> don't think it's enough to beat the upcoming hard AI's ..
   It was a first version, you have a better version attached. So, more 
comments?

How to beat the ai computer players

0. Introduction

    This document is intended to teach the first time
users of the game. It does not explain how to play with the game, it
only talks about strategies and describes the best ways to win the ai
players. Well, or not falling miserably in the first turns...

    Also, it is advisable to read the manual on the server.

0.1 How to set up the server?

    For a solitaire game to see how is the game and the
interface, just open two terminals and type in one terminal 'civserver'
or 'ser' if you're in the source directory, then in the other terminal
type 'civclient' or 'civ' and connect to the server. Then on the server
console type 'start'. This will set up the server with only one player
(you) and barbarians.

    For a game with other players just type 'set aifill
5' before typing 'start' at the server console. This will set up a game
with you and 4 ai players.

    There is another option which is the 'generator'
option. This chooses the type of world and the start positions in it.
There are 5 type of generators. But if you want an easy beginning, is
better to choose the 2 o 3 generator options. This will place each
player in an own island isolated from the other players. To do
so,  just type 'set generator 2' before typing 'start' on the
server.

1. Ai Levels

    There are 3 types of ai levels: easy, medium and
hard. In Freeciv 1.15.0 there will be a novice level to weak the ai code
even more.

2. Expansion

    One of the key things in a game is the amount of
terrain a civilisation has. More land means more population, more
resources and more trade. So the first thing to do is to build as many
settlers as you can to found new cities. And use this new cities to
build more settlers. You can use work lists to build a defender in every
city and then begin building settlers. 

    The best places to settle a city are near specials.
The cities use the tiles around its location (2x2) and the centre of the
square to produce food, shields and trade. So, the best places to settle
new cities are where this specials fall inside the 2x2 square. Provably,
the best for fast grow are Wales and Fish, which are in the ocean. So,
place your cities side by side the ocean tiles, that way you can build
a Harbour later, this will increase the food output in the future. 

    Try to not leave gaps between the cities, and create
the necessary cities to full fill all the terrain. Do it even though
there aren't specials. You can later improve the terrain and, in the
latest stages of technology, can transform the terrain.

    When building cities in the borders of your nation,
or where you now there will be attacks, it's better to locate the city
in terrains which has defense bonuses if you can do it. Don't locate a
city in a hill if this implies losing a special tile. Also, you can send
there defensive units of lastest technology to fortify the city.

    Do it until you are surrounded with enemy opponents.
Then, you can bodyguard settlers with defensive units to steal terrain
to your opponents just founding new cities in front of them. Or you can
stop founding new cities near its territory and sending the settlers to
other land not owned yet. You can send the settlers to land not owned
by your enemies, you can send your settlers to explore new islands with
triremes or caravels, or you can use the settlers to irrigate and
improve your home land.

    When you finish your expansion because you can
expand anymore, you must let your cities grow. To do it, do not keep
your cities building settlers, make them produce military units and send
them to the borders of your nation. You can use them to fortify your
cities or to attack your neighbours. And use the settlers to improve the
terrain. You can even build some caravans to establish trade routes or
build some wonders which can be helpful.

3. Governments

   There are four types of government you can be interested
in researching: Monarchy, Republic, Communism And Democracy. Monarchy
and Communism are the most useful to have war with your enemies, and
Republic and Democracy are the most convenient to have a peaceful
relation with your neighbours.

    You begin the game in Despotism. You must research
as soon as possible Monarchy or Republic, and switch to those types of
government when you have them. To do it set the long term objective to
Monarchy in the science report. There is a huge amount of corruption in
Despotism, and the trade-tax-science of far cities from the capital is
lost. So, surround you capital with cities at 2-3 tiles distance to
maximise the science output.

    When under Monarchy or Communism each city support
for free up to 3 units and military units doesn't cause unhappiness.
That's why these are the most militaristic government types.

    And under Republic or Democracy each units needs one
shield for upkeep. Each military unit outside a city causes unhappiness
and cities can revolt, which means that cities cease to produce. So,
managing wars with enemies is expensive and not productive. On the
other hand, this regimes are the good ones for economies based on
trade. There are trade bonuses unlike the previous ones. And also, with
this types of government you can make your cities grow fast, because
when cities celebrate the population of the city will grow at 1 citizen
per turn. Mainly, the differences between Republic and Democracy are
that with the former you suffer corruption and with Democracy no, and
with the later your cities and units are unbribable and citizens are
more easy to revolt when in war.

4. Terrain Improvement

    For a detailed explanation of the different terrain
follow that link.

    Well, in fact, the terrain improvement must be done
when you are still expanding and occupying new land. You want to
communicate all the parts of your home land. You must be able to send
military units to the border cities of your civilisation, in order to
engage in war with your enemies. You, also, need communications to
establish trade routes. To do this, you must make roads between cities.
And roads give trade, so that way you will be able to increase your
economy.
    Be aware that roading your land makes it easy for an
attacking force to conquer your cities. So have some attack and defense
units distributed all around.

    To make the cities grow you have to irrigate and
road the plains. First the plains, that will give you food, production
and trade (2/1/1). With that production you will be able to stop the AI
attacks.

    Then irrigate and road the grassland and create
mines in hills and mountains. Also make roads in hills and mountains. A
defender or attack there will have bonuses, then, this is a good place
to stop an invasion.

    Have in mind that if you place a worker of a city in
a hill or mountain, that will slow down or stop the grow of the city.
The AI does not have in mind this. This is why the production/wonder
cities of AI players are little cities. It's always better to have a
city of size 8 and production 15 than the same with size 3 and
production 7.

    Also, if you build a harbour in a coastal city the
default routine of the game will choose the ocean tile instead of the
irrigated ones. So, you will lose the production of the irrigated tiles.
So, rearrange yourself the workers.

    When you discover Railroad you can railroad all the
country. Which is advisable. Try to connect all your cities with rails.
And specially, railroad the mountains and hills because this gives
production, and the rivers which gives trade.

    Ah, you can implement the concept of supply lines -
the AI doesn't know how to do it. The supply lines are this
roads/railroads that connect your production cities to the front lines.
Normally, your production cities will be near hills and mountains, but
not near the border lines of your civilisation. So, you must move your
units to the front lines. Is not the same having a unit in the front
line in 1 turn that in 10 turns! The AI doesn't now this, so its units
will last to arrive to the front line. So, you can win this battle.

    Exploit the weakness of the AI. The AI doesn't know
about strategic cities and connected cities. To attack a civilisation
that occupies two peninsulas connected by a land pass you can conquerer
the cities that connect all the empire. The AI doesn't understand that
this cities are strategic to connect and protect the empire. Then
concentrate all your forces to fortify this fallen cities and conquer
first one half and then the other.

5. Trade

6. War

6.1 Defense

    The ai defaults to war when it has the first contact
with an enemy unit. So, the ai player will begin to build attack units
since the first time it declares war on you. But before building attack
units the ai will build barracks on its cities, so making the units more
powerful.

    Then, you must be able to neutralise this attacks.
One of the things you can do, is placing your capital and border cities
on hills or forests. That way you will benefit of the terrain bonuses
and your defensive unit will survive to the ai attacks, and will become
veteran. 

    Also its important to place veteran defensive units
in the border cities to make it difficult for the ai to win the attacks.
So a way to stop the attacks of the ai is to build the veteran defensive
units in the production cities inland of your country and to send them
to your frontier cities. Its very useful to use the resources of your
production cities to fortify your border cities.

    Remember to replace frequently your obsolete
defending units. You can upgrade them, or disband them in a city to use
its production units to build an advanced unit in the next turn.
    Its very important to have the lastest researched
defensive units in your border cities. The AI has omniscience and sees
what you have in our cities. So, if the AI player sees that you have
defensive units that it can't win, it will not attack that city and will
search for another, hopefully of another player, and will leave you
alone and in peace.

    The best defensive units are Phalanx, Pikemen,
Muskeeter, Riflemen and later Mech.Inf. Also Marines and Alpine Troops
are a good ones.

    Another thing that you can do is to build city walls
in your border cities and your capital. Also, you can build city walls
and fortify your wonder cities. 
    Also, its a good thing to build barracks in border
cities. In case of an emergency is a lot better to build a veteran unit
than a normal one.
    And later in the game, i'd better build city walls
in coastal cities to stop sea attacks. And, when someone researches
Ironclads, Destroyers or Cruisers, build coastal defenses to protect
them from sea attacks.

    And good thing to do is sending attacking units to
border cities to protect that cities and the inland ones. It's a way
better to attack before being attacked.

    You can also build diplomats and send them to your
border cities to protect them. I can also use them to bribe enemy units
or incite revolts in enemy cities. Anyway, the easy ai will not build
attack diplomats.

6.2 Attack

    To attack a city of another civilisation we have to
use the latest technology units. And also this units must be veterans.
That way your units are likely to survive and conquer the city.

    You can not conquer a city sending a unit alone to a
city. This is useless. You must build an army with defensive and
aggressive units, using the aggressive units to attack the cities and
its defenders, and your defensive units to protect the attacking units,
and later fortifying the occupied city. If you don't do this the ai
will counter attack and liberate the city, and the AI will stole
technology from you.

    Also, its good to know that the Horseman, Chariot,
Knights, Dragoons, Cavalry and later Armor, are good to attack cities
without city walls. This units are fast units and so are good to kill
enemy units that invade your terrain. To attack cities with walls your
need strong units like Archer, Catapult, Cannon, Artillery and later
Howitzer. 
    In fact, you can check which unit type is best to
build in the work list Tab of the City Window. In the Info Column you
have for each available item a short description of its properties
(Attack, Defense, Moves). Just choose the best attack unit to build. If
you have a unit with equal attack strength that another with more move
points, just build the last.

    And of course, always attack the weakest
civilisation with less technology. You can use diplomats to establish
embassies in that civilisations to see if you can attack them, or just
look at the its units you see in the map. Do not attack a city that you
can't conquer with your technology, just send them some diplomats to
incite revolt or sabotage that city.

    Also, exploit the AI weakness. The AI is vulnerable
to coordinate mass attacks. When the AI sees that is being attacked, it
will build defensive units instead of aggressive units. So, if you send
and army of 10 Howitzer is really easy to conquer AI cities. A very
useful strategy is to attack with Howitzers only once, and return to
your conquered city to recover hit points. You will be able to do it if
the distance between the cities is small and there is a road or railroad
path that communicates them.

    Always try to conquer a city in 1 turn. The AI can
attack in the next turn and kill all your units.Use Naval and Air units
before attacking with ground units.

    Another trick, is that the units of the AI player
does not look at a distance of a turn. If there are knights or alpine
troops in a city, they will not attack an armor 2 tiles away. So, if
you want to attack a city place your fast units 2 tiles away and the AI
will attack you!! This also works for the diplomats.

6.3 Barbarians

    Barbarians can be turned off ( 'set barbarians 0' on
the server console).

    If you leave huge masses of unexplored land or
unsettled land, barbarians will appear. It appear in form of armies on
ground tiles or in the sea - the sea raiders!!! -.

    They are an AI controlled player. But it's an
special player. It only build aggressive units and send them to attack
your cities without bodyguards. So, to liberate your fallen cities just
build an army of fast attackers - Knights or Dragoons - and attack the
cities. They almost never build defensive units, so its easy to
reconquer a barbarian city.

6.4 War under different governments

    There are differences in the level of 
unhappiness that the military units cause under different types of
government.
    The best government to have a war is Communism.
Under Communism and Monarchy, military units outside a city does not
cause unhappiness. And you have limited martial law. Military units in
a city reduce unhappiness. Up to 3 units can be used to make citizens
content and not-revolting. So, you don't have to build Coliseums or
Cathedrals to keep the people content.
    Under a Republic or Democracy, each military units
outside a city causes unhappiness. You will have to increase the luxury
rate of your empire - which cost you money or science - or you will
have to build improvements to your cities.

   Another thing to have in mine, is that the military units
are not free. They cost shields to build and mantain. You must use 1
production point - 1 shield - to upkeep that unit each turn. So, the
units already produced by your civilisation reduce the capacity to
generate new ones or to build new improvements.
    Under Monarchy or Communism you can upkeep 3
military units for free. This is very useful. That way you can use the
defensive military units to impose martial law and defense the city.
And you can produce military units in your production cities, send them
to the destination city, and make it its new home city. That way you
don't penalise your production.
    Under a Republic or Democracy you have to support
the upkeep of each military unit. So, only produce the necessary units
when you want a defender for a know threat, most attacks aren't
surprising.

7. Diplomats & Spies

8. Technology

    In the long term, you must be the first civilisation
in the world in research. But it's only necessary to have the right
techs. The technology you don't research can be told by occupying enemy
cities or stolen by diplomats.
    Technology is the most important variable in the
game. If you're the first civilisation with regard production but you
are the last in technology you will end up killed. A huge army of
warrior can't do anything against a veteran cavalry.

    If you see that you're in tech lead, and need money
for buying City Walls or Coastal Defenses or other improvements, stop
research and generate money, but don't do it for a long period of time.

    The strategy in choosing the long term objectives
for developing technology differ whether you are alone in an island or
in a continent surrounded with enemies.

    When you're alone in an island you can research
first attack technologies and them defensive technologies. You must
research technologies to build naval units (Automobile, Combustion,
Steel, Magnetism, Navigation, Map Making) and naval defenses
(Metallurgy). Also, you must develop the technologies for ground
units.  The most successful strategy in this scenario is going for
Republic, Map Making, Horseback, Magnetism or Steam Engine.

    If you are in a continent with enemies, i'd better
research defense and attack ground technologies. First the defensive
ones.
If you are in the beginning of a game is recommended to research first
'Horsemen' And 'Bronze Working' to be able to build Horsemans and
Phalanxs to resist the ai attacks. Then research Monarchy. Later on you
must research 'Iron Working' and 'The Well'. And then, go for the rest
of ground technologies.

9. Wonders

10. Happiness