Fanorona starting setup
Abstract strategy game
Fanorona has three standard versions: Fanoron-Telo, Fanoron-Dimy, and Fanoron-Tsivy. The difference between these variants is the size of board played on. Fanoron-Telo is played on a 3x3 board and the difficulty of this game can be compared to the game of tic-tac-toe. Fanoron-Dimy is played on a 5x5 board and Fanoron-Tsivy is played on a 9x5 board - Tsivy being the most popular. Black and white pieces, twenty-two each, are arranged on all points but the center. The objective of the game is to capture all the opponents pieces. The game is a draw if neither player succeeds in this. Capturing is done by either approaching or withdrawing from opponent's pieces.
Fanorona is very popular in Madagascar. According to one version of a popular legend, an astrologer had advised King Ralambo to choose his successor by selecting a time when his sons were away from the capital to feign sickness and urge their return; his kingdom would be given to the first son who returned home to him. When the king's messenger reached Ralambo's elder son Prince Andriantompokondrindra, he was playing fanorona and trying to win a telo noho dimy (3 against 5) situation, one that is infamously difficult to resolve. As a result, his younger brother Prince Andrianjaka was the first to arrive and inherited the throne.
The Fanorona board consists of lines and intersections, creating a grid with 5 rows and 9 columns subdivided diagonally to form part of the tetrakis square tiling of the plane. A line represents the path along which a stone can move during the game. There are weak and strong intersections. At a weak intersection it is only possible to move a stone horizontally and vertically, while on a strong intersection it is also possible to move a stone diagonally. A stone can only move from one intersection to an adjacent intersection.
There exist variations of the rules; this is the main variant.
Using 10.000 games with Alpha-beta pruning players the game-tree complexity and state-space complexity can be computed. It turns out that Fanorona has a game-tree complexity of 1046 and a state-space complexity of 1021.
In 2007 the game of Fanorona and smaller variants has been solved weakly. It turns out that this game is a draw. Both the moves f2-e3A and d3-e3A lead to a draw.