The Game of Amazons - Invader

Rules of the Game
Masters Projects
Other Programs


According to Greek mythology, the Amazons were a race of warrior women within ancient Greek civilization. They originated from the area around the Caucasus Range and settled in Asia Minor on the shores of the Black Sea. Women entirely ruled their society, and two queens, one for defense and one for domestic affairs, shared the sovereign rule.

Amazons is a two-player board game invented in 1988 by Walter Zamkauskas of Argentina. El Juego de las Amazonas (The Game of the Amazons) is a trademark of Ediciones de Mente.  It can be played on boards of arbitrary n x n size, however, it is usually played on a 10 x 10 board.

Rules of the Game

The Amazons game can be played on boards of arbitrary n x n size, however, it is usually played on a 10 x 10 board. Each player, white or black, has four amazons. The rules of the game are as follows:

A) On a 10 x 10 board, the white player starts with amazons on locations a4, d1, g1, and f4, while the black player begins with amazons on a7, d10, g10, and j7.

B) The white player starts the game. Each move contains two mandatory parts:

  • The player's amazon moves like a chess queen - any number of squares in a horizontal, vertical or diagonal line.
  • Once it gets to its final position, the amazon throws an arrow that also moves like a chess queen. The arrow permanently blocks the board square it lands in.

C) Both the amazon and the arrow it throws must move along a line that is not occupied by another amazon or blocked by an arrow.

D) The last player able to complete a move wins the game.


Below is a version of Invader that was posted on February 1, 2003.  It is the mini-max version of Invader and is essentially the same as the version that won the silver medal at the 10th Computer Olympiad held in Taipei, 2005.

Zipped download of mini-max Invader:  Invader v. 2.1

The following version was posted on October 15, 2008. It is the MCTS (really UCT) version of Invader that won the gold medal at the 13th Computer Olympiad held in Beijing, 2008. Invader has gone on to win gold medals at the 14th Computer Olympiad in Pamplona, 2009 and at the 15th Computer Olympiad at Kanazawa, 2010. The current version is little changed from the version posted below.

MC/UCT version of Invader: Invader.exe


Please try the program and send comments, suggestions, observations, bug reports, spectacular wins, etc. to

Masters Projects

I am currently seeking students interested in doing masters projects in this area.  Invader is currently the top Amazons playing programs in the world and so this is an opportunity to be involved in an exciting and current project.  Perhaps with your help we can keep our title a little longer.

Other Programs

  • 8QP - Johan De Koning (The Netherlands)
  • Amazong - Jens Lieberum (University of Basel, Switzerland)
  • Amsbot - Michael Buro (University of Alberta, Canada)
  • Anky - Patrick Hensgens (University of Maastricht, The Netherlands)
  • Antiope - Theodore Tegos (University of Alberta, Canada)  --currently unavailable
  • Arrow - Martin Müller (University of Alberta, Canada)
  • Gamazons - Ron Yorgason, et. al.
  • Tanazon - Yasushi Tanase
  • Yamazon - Hiroshi Yamashita

Links (all quite dated)

The Definitive Amazons Page
Amazon Unofficial Home Page
The University of Alberta GAMES Group - Amazon Research
The Chess Variant Pages - Amazons