The diagram shows the board and the pieces in initial position. There are two players, black and white. White begins. Players move - and must move - in turn.
Capture has precedence over a non-capturing move. If the player to move has no capture to make, he has the following options:
A king is a promoted man.
A man moves one square straight forwards or one square straight to the right, provided the target square is vacant. If a man thus reaches a square of the promotion area, the 11 squares adjacent to the red band on the side, it promotes to king. A king moves straight over any number of unobstructed squares.
Capture is compulsory. Men capture straight in any direction by the short leap, kings capture straight in any direction by the long leap.
- If a man is on a particular line, and next to it on that line is a square occupied by an opponent's piece, then the man captures the opponent's piece by jumping over it to the square immediately beyond, which must be vacant for the capture to take place. If the man can proceed in a similar way in the same or the perpendicular direction, it must do so.
- If a man ends its move on a square of the promotion area, it is promoted to king. If a man in a capture reaches the promotion area, it may still be under the obligation to perform the capture to its completion. In that case it must keep on capturing as a man. If on completion of the capture the man is not on the backrank, it does not promote.
- A king captures straight by the long leap. It is subject to the same completion rule: if it can proceed in the same or a perpendicular direction, it must do so.
- A multiple capture must be completed before the captured pieces are removed from the board.
- A king making a multiple capture may visit a square more than once, but a piece may not be jumped more than once.
- Majority capture precedes: if presented with a choice of captures, the player must beforehand select the one that brings the highest number of pieces, a man and a king both counting as one piece.
If a player has no legal move he loses the game. This may come about either by being eliminated or being blocked completely. Draws may occur by mutual agreement or 3-fold.
International Draughts got its name from being the Checkers variant that is the tournament standard in many countries of the world. Its ruleset with long range kings, backwards capture by men, and majority capture offers a wide range of amazing tactics. Further, like most traditional European variants, it is played on one color of the Checkers board only, thereby enforcing that men must move forwards. No sidewards movement is possible. That way, every move is a decision with lasting consequences, and detailed strategies are needed to cope. All in all, it is a very good game.
But International Checkers has a well known weakness: if one player gets a king, his opponent generally needs a significant material advantage to win the game. In the case of a king on the main diagonal, the opponent needs a minimum of four kings to win the game, otherwise it is drawn. For this reason, games often end in a draw even between mediocre players.
There is a reason for this behavior. When we look at the traditional Checkers board, we see that we can change the representation:
Both pictures show the same position - a Coup Raphaël - and the representations are isomorphic. In the first, traditional version, there are unused fields and kings would move like bishops in Chess (would because there are no kings in that position). In the second version, there are no unused fields anymore and kings would move like rooks in Chess. The second version also shows that the Checkers board hides an unusual geometry.
Let's have a look at Turkish Checkers, aka 'Dama'. In this game the full square board is used and kings move like rooks, as in the second representation of International Checkers. On the square board, however, two kings versus one is a win. So, it is the hidden geometry of the traditional European Checkers board that is to be blamed for the draws. (As a side note: Turkish Checkers does not enforce that men move forwards, providing another source for draws as can be seen easily in a king versus man endgame.)
For that reason, game designers have looked at Turkish Checkers in order to improve on International Checkers. It was also obvious that the enforced progress of International Checkers had to be kept as a feature because it makes the game strategically deeper and because it avoids a source of draws. Games arising from this approach are Croda and Dameo. In my opinion, these hybrids are better than the games they were based on. Yet, they lack a feature of traditional checkers, namely that of having 'the move' (opposition).
I had a different issue with Turkish Checkers. In Turkish Checkers, a man has one forward and two sideward moves respectively captures, whereas in International Checkers, you get two forward and two backward. The latter version seemed more active to me. One night, while going to bed, it occured to me that you could turn the board of Turkish Checkers by 45 degrees. That way, one got more "active" behavior as well as keeping the decisive endgames since you do not change the geometry. Oh, and yes, progress by men is enforced, too. It took some minutes until it dawned on me that movement and capture of Turned Turkish Checkers are isomorphic to International Checkers. It is just the board that is different, requiring a setup position as well as a promotion area of its own.
A setup came naturally: leave the line crossing the middle of the board and the two adjacent lines empty. With just the line in the middle left empty, the game would be too crammed. In other words, the setup would look like in Halma. On an 8x8 board, the board of so many games, that would make 21 men per side on 64 fields. Compared to International Checkers with 20 men on 50 fields, that seemed reasonable.
There were two major questions left. Number one: what should the promotion area be? Choosing the opposite corner and that corner only would be the least arbitrary decision. However, it signalled to give a long and slow game. Another idea was to take the hint from International Checkers and to choose all fields on the edge which are covered by the opponent in the setup. The advantage being that the game would be faster with a major goal, the promotion fields, closer in reach. It tends to make a game more appealing.
Play testing showed that king and man versus king is a win. That looked promising. Further, while the promotion fields seem to be in reach, it is not trivial to get there. The game would not be too "single minded".
There was a second open question. Was I really the first one to think of this? I could not believe it. Yet, Google did not show a predecessor. So, I checked with Christian Freeling and Arty Sandler. Neither of them knew a predecessor as well. And Arty asked me, if I had a name for the game. He wanted to implement it at iGGameCenter. My simple mind conjured up Harzdame, a pun on the German name for Checkers and a mountain region close to which I live. For the implementation, Arty turned the board back by 45 degrees. In this representation, men have to move up and right from their player's point of view. The promotion area is shaded in red on the edge of the board.
Many thanks to Christian Freeling and Arty Sandler. Christian's detailed analysis of Checkers at Mindsports was the inspiration for Harzdame. Further, Christian states that it is easy to predict the behavior of certain games. So far, Harzdame has behaved the way as expected, and I see it is a corroboration of Christian's theory. Arty has implemented the game, submitted it here at BGG, been around for further playtesting, and given me some painful losses. Lastly, thanks to all who have played and enjoyed the game.