Copyright (c) 2003 Grupo de los Lunes

This game is played on the following 9x9 square board:

GROUP - an orthogonally connected set of stones of the same color.
TURNS - On the each turn, each player drops on two empty cells, one black and one white stone (orthogonally or diagonally) adjacent to each other. 
When there are no valid moves, the game is over.
GOAL -  Each player sums the squares the size of his three biggest groups (one player owns black stones, the other white stones). The winner is the one with the highest total.
If the values are equal, compare the next white and black group to decide. If still equal, repeat while it is possible. 
If the previous procedure does not find a winner, the game is a draw.
An example

Black's turn. A possible move for Black would be inserting a pair of stones at [1][2], placing a black stone at [1] (making a group of size 3) and the white stone at [2]. 

This way, the cell at c1 is unusable, and White cannot connect [2] with the two white stones above.


The game is ended. The marked stones refer to the three largest groups for White and Black.

Each final score is the sum of the squares of those groups sizes. So, White = 72+62+52 = 110 and Black = 82+52+52 = 114. 

Black wins.

The "Grupo de los Lunes" is a sporadic group of players dedicated to play and to create abstract games. Tonga was designed and tested by Ariel Arbiser, Pablo Coll, Alejandro Donnantuoni, Marcos Donnantuoni, Rodolfo Kurchan, Oscar Lagioia, Pablo Milrud, Enrique Pavese, Gustavo Piņeiro, Jaime Poniachik, Ivan Skvarca & Pablo Suarez.

Tonga was the second place at the 2004 Shared Pieces Game Design Competition.