​Rules of the Game

1.  Introduction 

Opprimo is a board game played between two players. It is a game of skill and strategy which can normally be played in under 20 minutes. At the start of the game, the players command a force of ten pieces called Soldiers which they try to maneuver through the board to gain positional advantage to penetrate enemy lines, convert enemy pieces to their side, promote Soldiers to Knights, and eventually surround the enemy’s most vital piece, the King.
 
One unique characteristic of the game is that from the game’s start to its end, all Soldiers take an active part in the battle. No Soldier is removed from the board except when it is replaced by a Knight when promoted. Since the pieces can change sides, the players will at times find their respective forces either depleted or reinforced. This characteristic is what makes Opprimo intriguing, challenging, and entertaining to players young and old alike.

2. The Board
 
The game is played on a board composed of sixty-six (66) triangles (Figure 1). The areas bounded by colored lines are the Castles or territories occupied by the two contending forces at the start of the game.

​​​​Figure 1. The Game Board with the colored areas showing the opposing Castles. 

​3. The Pieces
 
There are eleven active pieces on each side composed of ten Soldiers, all equal rank, and one King. One player gets the yellow pieces and the other the red pieces.
 
There are also 20 Knights (10 yellow and 10 red), each of which is placed on the board whenever a Soldier has been promoted. Fig. 2 shows an example of the playing pieces. 

Figure 2. The Pieces

4. The Objective of the Game
 
The objective of the game is to surround or trap the opponent's King (Figure 3). The King is said to be surrounded when the three points of the triangle on which it stands are occupied by the opponent's Soldiers or Knights or a combination of both.

Figure 3. The objective of the game is to surround the opposing King.

​5. Start of the Game
 
To start the game the players set up the board by laying it flat on an even surface. Then they arrange their pieces on the board as shown in Figure 1. The Soldiers are placed on the corners of the triangles. Printed on the board are small yellow and red dots to assist the players in positioning their pieces at the start. The King is placed inside a triangle.
 
The player with the yellow pieces always makes the first move. The play proceeds with the players making alternate moves.
 
6. Movements of the Pieces
 
A Soldier moves along the lines in a FORWARD DIRECTION ONLY, one step at a time, from one intersection to another, vertically or diagonally (Figure 4a).

Figure 4a. A Soldier can move forward only, one intersection at a time.

​The King also moves one step at a time to any triangle adjacent (side-by-side) to it. It cannot, however, step outside of its own Castle. Figure 4b shows the movements of the King. The King’s move constitutes one legal move and, therefore, the next move belongs to the opposing player. Thus, the King and the Soldier or Knight cannot be moved at the same time.                                     

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Figure 4b. Movements of the King.

​7. Conversion
 
One interesting aspect of the game is that a player can increase his or her force and at the same time diminish his or her foe's by using the game's innovative feature. It is called Conversion – the process of making an enemy piece change sides or its color.
 
Conversion is accomplished by making a Soldier jump over an enemy Soldier as long as there is a vacant intersection right behind the enemy Soldier (Figure 5a). The Soldier that has been jumped over is flipped and is said to be converted (Figure 5b).
 
Conversion constitutes one move and is executed in the same manner as the ordinary movement of the Soldier. This means that the direction of conversion must only be either vertically or diagonally forward. Backward conversion is not allowed.

Figure 5a                                        Figure 5b

Conversion is not mandatory. That is, a player can choose to not convert an enemy piece.
 
A Soldier can be converted more than once but ONLY ONE Soldier can be converted at a time. Thus, the conversion moves as shown in Figures 5c and 5d are NOT allowed. 

Figure 6: The Knight's Movements.

Figures 5c and 5d, respectively. These conversion moves are not allowed.          
 
Due to its position on the board, the King cannot convert any piece.
 
8. Promotion
 
When a Soldier reaches any of the three farthest points on the board (marked by a shield), it becomes a Knight and acquires additional movements. It can now move and convert backwards vertically and diagonally but still ONLY ONE step at a time (Figure 6). 
 
During promotion, the player removes the Soldier from the board and puts a Knight in its place.                                                                                                 
                                                                                                                                                                                              Note that the Knight can also be converted. As such, it reverts to a Soldier. When this happens, the player that makes the conversion removes the Knight from the board and replaces it with his or her own Soldier. 

  
9. Additional Notes
 
A. A Soldier can move along ALL the lines on the board, and this includes the vertical lines on either side of the board.
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B. Figure 7 shows an end game position won by the yellow player even though a red Soldier is threatening to convert a yellow Soldier. 

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​Figure 7: Yellow wins.
 
C. The King can move into a triangle whose three corners are not occupied by enemy Soldiers. Thus, if only one or two corners are occupied, the King is free to move into the triangle.

D. When a player succeeds in trapping the enemy King, the player says “Trapped” and the game ends.
 
E. When a player resigns, he or she simply states, “I resign.”
 
F. A game ends in a draw when both players agree upon it.