Halatafl is a mixture of Arabic Alquerque and the Viking game Hnefatafl. In Halatafl the object for both parties is to reach any of the two corners of the board located behind the enemy forces. The pieces move one step orthogonally, i.e. forwards and sideways, but not backwards. However, capturing backwards is allowed.
Only orthogonal capture is allowed. If an adjacent square is occupied by an enemy piece and the square directly behind is vacant, then the piece must jump over it and capture it, as in Checkers. Several pieces may be captured like this in a single turn. Should a player put a piece in his own corner, then he loses. However, jumping via one's own corner does not lose.
A good strategy is to gain majority on a wing and break through to reach the enemy corner. Be prepared to sacrifice one or more pieces in order to achieve a strong position, e.g., a piece that threatens to reach an enemy corner.
(The above builds on my own assumptions about different possibilities of rule interpretation. I have not made a thorough historical research of the subject matter.)
Halatafl is sometimes referred to as the medieval game Fox and Geese. However, as Sten Helmfrid points out, the name probably refers to the very board which the Vikings used for Hnefatafl. Obviously, this board was also used for the game which uses a similar initial setup as Alquerque, although with many more pieces. I will from here on use the term Halatafl for this game (this notion is supported by this site about Viking games). As the rules of Halatafl are only partially known I have researched different possibilities of rule interpretations, testing the different rules in a computer program. For an earlier guess of how this game was played, see Appendix.
Firstly, we can exclude the notion that capture can be made in any direction, including diagonals, and that it's also allowable to jump one's own pieces. This will generate a completely wild situation on the board that is wholly uncontrollable, even for a computer. Moreover, the notion that winning is achieved by simply reducing the opponent's men to five creates a dull game.
In the Spanish version of Alquerque (a forerunner of Halatafl) there is no piece promotion. Capture can also be made along diagonals, and the object is to reduce the opponent's men to zero. But this ancient Arabic game is played on a smaller board (5x5), and the complexity is further reduced by the fact that one is obliged to follow the marked lines and diagonals. Half of the diagonals are closed. I contend that only orthogonal movement was allowed in Halatafl. This coincides with the piece movement in Hnefatafl which does not utilize diagonals.
Among the archaeological artefacts there are boards with no carved squares, but only the two long diagonals (look here). I contend that these are Hnefatafl boards which were also used for Halatafl. The diagonals only serve as help for orientation and are not guides for piece movement. The fact that neither diagonals nor squares are properly marked proves that the game did not occur along the diagonals. On a 7x7 board it is virtually impossible to think ahead and foresee moves along diagonals if you don't play on a properly marked checker pattern or diagonal matrix (like on an Alquerque board). However, if you only play orthogonally, the artefact boards will work quite well.
This rhymes with what HJR Murray says, that during the Middle Ages, diagonal lines on lined boards tended to be omitted, with a consequent disuse of all diagonal moves ('A History of Boardgames', p.9, 1952).
In Hnefatafl win is secured for the one party if a corner square is reached. Also in Halatafl we know that the squares had a special significance as they were left vacant. If we apply the Hnefatafl corner rule also on Halatafl the game suddenly comes alive and makes very much sense. It then becomes a quite functional mixture of Alquerque and Hnefatafl. Halatafl is more strategical in character than the other two medieval games. (As a besides, if we choose to apply the corner rule then we cannot allow diagonal movement, anyway, because it can be shown that white will forcibly lose piece in the opening position, regardless if we allow backwards movement of pieces or not.)
The idea that the pieces move orthogonally until they happen upon one of the two long diagonals whereupon they can also move diagonally, is an implausible idea. The game is tactically complex enough. It would be quite impossible to foresee tactical turns if such erratic piece movement was allowed.
It is likely that the Vikings wanted to emulate a medieval battle situation. The men must be under strict discipline and have no need of squares to guide them. They form their ranks perfectly anyway. Each man faces an adversary in the enemy army. It is also against this man he will strike (orthogonal capture). The men cannot go backwards, which is consistent with Viking warfare because retreating men could cause a catastrophe, since the lines would break up.
However, the men are allowed to capture backwards as an enemy behind your back cannot be ignored. The explicit object of a battle is not just the killing of men. It could be the capture of a castle, for instance. This game provides such an objective in the two "castles" in the form of the corner squares. So, clearly, this game emulates a medieval battle situation.
The initial position looks crammed, but the situation soon dissolves due to many piece exchanges. The opening position is unbalanced while white has a spatial advantage on the left wing and vice versa. This creates a strategical tension which is missing in many games of checker type. The crowding on the wings precludes the simplistic strategy of immediately invoking operations there and attacking the corner squares. There are no moves on the wings. First the position in the centre must be resolved.
In the middlegame maneuvering ensues, interspersed with tactical combinations. Overall, the game has a less forced character than Anglo-Saxon Checkers, for instance. Due to the relative importance of positional factors one is not hopelessly lost if one loses a man or two. Positional factors could compensate for this, and one can also figure out a clever tactical stroke which conquers a piece back. This often occurs in the middle game if a lonely man strays too far into the enemy position. Such a piece is often lost, not seldom due to a tactical combination (actually, this is a factor which mimics reality, too).
All in all, Halatafl is not only interesting for historical reasons. It is attractive due to its blend of strategical and tactical aspects. Opening, middlegame, and endgame, are all interesting in their own way. A skilled player could often win against an inexperienced player in less than 20 moves, by reaching the corner square by way of a combination. The endgame, too, is quite volatile since there are fewer enemy pieces in the way of the corner square. Due to this draws are not common in this game.
Note that there is an alternative way of winning than reaching a corner square or capturing all the opponent's pieces. This would be to force an enemy piece into one of his own corner squares. This could be achieved by sacrifice of a piece, since capture is obligatory. But this situation will occur very seldom. Analogous with the rule that a piece can jump via his own corner square, a jump via an enemy corner will not cause victory (as the move is not finalized).
You can download my free Halatafl program here (updated Dec 2, 2005), but you must own the software Zillions of Games to be able to run it.
How Halatafl rules were earlier (mis)understood.
The initial set up is as can be seen above. The two sides have 22 identical men set up on the board. The centre and corner squares are left empty. The pieces can be moved in two different ways; either they move one step at a time either forwards, sideways or diagonally along the marked lines (the two long diagonals) but never backward. The other way they can move is by jumping over a neighboring piece to a vacant square behind it. They may proceed jumping as many times as possible in any direction or even backwards. The jump can be made over any piece - your own or your opponent's. If you jump over one or more of your opponent's pieces they are captured and removed from the board. White opens the game by moving a piece onto the centre square. Black takes it by jumping over it and the game proceeds until one of the players has fewer than five pieces left - and loses. A jumping piece may make an intermediary landing at a corner square. However no piece is allowed to stay there.
© M. Winther 2005