Dragons is a tile placement game in which two players strive to complete sinuous loops of their colour.

Cameron Browne (2009)

Rules

Tiles: Two players, Green and Red, share a common pool of 50 hexagonal dragon tiles. Each tile shows shoulders on the front and tails on the back in both players' colours (Figure 1).


Figure 1.  A dragon tile showing shoulders (front) and tails (back).

Play: The opening player places a tile of their choice in the centre of the playing area. Players then take turns adding a tile of their choice adjacent to at least one existing tile, such that edge colours always match.

Auto Moves: If a tile placement creates a gap at which only one tile rotation matches, then that tile is automatically placed there. This will occur for gaps with three closed sides if two or more consecutive sides are of the same colour.

Each move may trigger multiple auto moves, such as move a in Figure 2 which triggers auto move b which triggers auto move c.



Figure 2.  Placement 'a' triggers auto moves 'b' and 'c'.

A player's move consists of their tile placement in addition to all subsequent auto moves. All possible auto moves must be made each turn; players cannot decide to stop or undo their move halfway through.

Gap Moves: The current player must play at a gap with three closed sides, if any exist (these will only occur if the three closed sides are alternating colours). For example, the current player must play at either d or e in Figure 3.



Figure 3.  The next move must be at 'd' or 'e'.

Aim: Players win by forming a loop of their colour that passes through six or more tiles. For example, the mouth of the happy dragon in Figure 4 is a winning loop for Red.


Figure 4.  A game won by Red.

The two smaller loops shown in Figure 5 do not constitute wins as they only pass through three and four tiles respectively:



Figure 5. Small loops (less than six tiles) do not win.

If a move completes winning loops for both players, then the longest loop wins. If both loops are the same length or neither player wins before the tiles run out then the game is drawn.

Remember that the win test is not made each turn until all auto moves have been made!

Strategy and Tactics

Gap moves are useful for slowing down the opponent or wresting the initiative away from them. Any move that creates one or more auto move threats can be deadly if it also creates a gap move that stops the opponent answering those threats next turn.

Virtual Connections: Two paths of the same colour entering a gap from consecutive sides are virtually connected. For example, the two red paths entering gap f in Figure 6 (left) are virtually connected as the only possible tiles that can be played there (middle and right) both connect them.


Figure 6. Virtually connected paths.

Virtual connections are almost as good as actual connections as they are unbreakable, quicker to establish and harder for the opponent to spot. A loop made of virtual connections cannot be blocked but is not necessarily a guaranteed win; it may take several moves to actually close it, giving the opponent the opportunity to delay the closure with gap moves and possibly set up an even more immediate threat.

Danger Patterns: Figure 7 (left) shows a common danger pattern: Red can win from this position regardless of whose turn it is to play. Green's best response is the forced tail tile at gap g (middle) which allows Red to seal the victory next turn with move h and auto moves i and j (right).


Figure 7. A winning pattern for Red.

Notes

Auto moves will always be shoulder tiles. Gap moves will always be tail tiles.

The fact that all three-sided gaps are immediately completed by auto or gap moves means that no gap will ever have more than three closed sides, hence concave hollows and holes will not form and the board will tend to expand outwards layer by layer to remain generally convex.

Variants

Tiebreaker: Instead of declaring the game drawn when the tiles run out, players may agree to award the game as follows:
1. The owner of the largest closed dragon (no open ends) wins; or
2. The owner of the largest closed dragon loses; or
3. The owner of the dragon with the most holes wins; or
4. The owner of the dragon with the most holes loses; or
5. The player with the lower ranking wins.

Tantrix Scoring: Each dragon scores 1 pt per hole, doubled if the dragon is closed. The winner is the player with the highest scoring dragon after all tiles have been played.


History

Dragons tiles and rules by Cameron Browne and copyright (c) Cyberite Ltd 2009.

The tail-tile design initially consisted of six disjoint tail ends, however this was found to have a detrimental effect on play as two or more dragons originating from the same tail-tile could never join; each tail-tile effectively radiated six boundaries that could not be crossed. The new design with crossed tails solves this problem and allows dragons of more interesting topology to develop.

Dragons can be played on Richard's PBeM server, please check out the help file for more details and challenge me (camb) to a game any time.


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Site designed by Cameron Browne © 2009.