# WebFortress

## The Goal

You must have more influence than your opponent on a 6x6 board at the end of the 21 turns. You gain influence on the board by building castles. You start as the white player.

## How to gain influence

A castle has influence on the four squares next to it, as you can see below (monochrome icons... on color display it will look better than that, but everyone must be able to see this.)

Your influence is the total of all flags and castles. A castle may have one, two or three flags, which correspond to the amount of influence radiated by the castle. To build a castle, click on a square -if not occupied by your opponent-, to build a two-flags castle, click on one of your one-flag castles, for a three-flags castle, click on a two-flags castle. See below the three castles.

An empty square belongs to you only if you have more influence on it than your opponent. The total of influence over one square is the sum of castles of one side minus the sum of the castles of the other side which are next to this square. A two-flags castle counts as two one-flag castles, three for three-flags castles.

Top left : 0 white castles - 2 (1+1) black castles = -2 -> a black flag
Top right : 1 white castle - 1 black castle = 0 -> an empty square
Bottom left : 2 (2) white castles - 1 black castle = +1 -> a white flag
Bottom right : 3 (2+1) white castles - 0 black castles = +3 -> a white flag
Middle : 3 (2+1) white castles - 2 (1+1) black castles = +1 -> a white flag
The score : 5 for the white player (3 flags + 2 castles) 3 for the black player (1 flag + 2 castles)

## How to destroy a castle

A castle is destroyed if the opponent has more influence on the square than the owner of the castle. The influence is the sum of the castles of one side minus the castles of the other side, x-flag castles worth x castles.

Top to bottom and left to right
1-white protected by 1 white castle 1+1 = +2
2-white protected by 1 white castle 2+1 = +3
1-white protected by 3 white castles (2+1) and attacked by 3 black castles (2+1) 1+3-3= +1
2-black protected by 1 black castle and attacked by 1 white castle -2+-1+1 = -2
1-black protected by 1 black castle and attacked by 1 white castle -1+-1+1 = -1
1-black protected by 3 (2+1) black castles -1+-3 = -4

If a castle is on a 0 influence square, it closes its door. like this (middle: 1+(2+1)+(-2+-2)=0)

If the white player wants to protect his castle, he must increase the level of the castle or the level of one of his two castles next to it. If the black player wants to destroy the castle, he must increase the level of one of his two castles next to the white one. In the following example, the black player played on the bottom-center square to destroy the white castle in the middle.

## How to win the game

You only have to be smarter than the computer !!! I have no time right now to build a more powerful program than this one. If you think of a good way to improve the level of the program... email me !

## Misc.

This is the WWW version of Xfortress which i made in 1993. It is based on a game i saw on an Apple II* ten years ago. Xfortress can be downloaded freely from your best ftp server. If you want to improve the strategy, look at "types.h" to see the structure of datas, so i can use it directly in this WWW version.

* - Apple II is a trademark of Apple Corporation Inc.

Xfortress and WebFortress © 1993-1995 by Yves Lafon