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Allemande

Period

Modern

Category Experimental

Description

Allemande is a drawless, square board-crossing game that does not allow diagonal connections.
It evolved from an idea similar to 'Connecticut' by Corey Clark, with comments and suggestions from Luis Bolaños Mures
based on an unpublished polyomino connection game of his.

The principle is that for a crossing connection game on a square board, where diagonal connections are not counted for the win condition, they must be disallowed to avoid stalemates. - But may be allowed in the case where a true connection between those pieces has been established.

In such a case, four simultaneous placements are the minimum required to avoid any conceivable stalemate position.

Thus, in this game up to 4 sequential placements are allowed per turn.

At the end of the turn, no same-color diagonal relationships may remain between pieces that are not otherwise connected orthogonally.

During the turn, however, diagonal placement is allowed, as long as it is resolved before the turn ends.

The name Allemande comes from the dance, which is stately and in 4 steps.

Implementation:
I implemented the 4 placements by using play from a hand of 4. The hand is replenished before a player's turn. This works well as a way to visually keep track of how many pieces have been played. Select moves are used to make each move a single decision, despite the movements.

Connection is determined by whether the lowest left-edge stone can step a continuous path to the upper rightmost stone.

Issues with implementing this game in Ludii:
1. Ludii does not have a turn structure which would allow filtering for illegal diagonals at the end of 4 placements and reversing the entire move. (and that approach would be very inefficient anyway.)

Therefore each diagonal placement is being resolved on the next placement, and is not allowed as the forth placement.
And voluntary passing is not allowed when the board is in an illegal state.

This has the side effect that the placement sequence is not entirely arbitrary; but it also reduces AI load.

2. However, when this approach is taken and the placement cannot be resolved, Ludii supplies an automatic pass that does not allow post processing, leaving the board in an illegal condition of having a diagonal placement.

My work-around is to create a reversing move for diagonal placements, but this allows endless cycles.

3. Thus (meta (no Repeat PositionalInTurn)) is needed.
To allow the reversal, the piece states are not returned to the original values.
This solution also prevents endless replay variants, by limiting the choices available.
It also gives a Human the choice to use 'Undo' in order to explore other placement sequences.

4. A forced pass can happen after the removal, but leaves the board in a legal position.

The AI tends to play out these reversals, and can get caught by the lost opportunities.

Human players will quickly become familiar with what sequence of placements is needed for their purpose, and, if necessary reverse their moves with the undo button until they achieve the desired goal.

In any case, with 4 placements per turn, the AI's are not very good at the game.

Rules

Goal: To Win, connect the groups of stones at opposite edges.

On your turn place up to 4 stones.

Restriction:
You may not place a stone diagonally from another stone of your color, UNLESS the stone is connected through othogonal links after you have placed your next stone in the same turn.

If you place in the wrong sequence use the Undo button to go back.

Do not select the stone to reverse the move as this limits your options to move elsewhere.
That option is just there as a work-around for the Ludii system.

There are 2 versions:
1. Placing pieces on any empty spaces allowed in the above rules.
2. Restricting successive placements in the turn to locations around the previous placement.
This keeps all the pieces played in one turn, as a group.

Author

Dale W. Walton

Creation date

2022

Ludeme Description

Allemande.lud

Concepts

Browse all concepts for Allemande here.

Identifiers

DLP.Games.1564


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