Slyde is a territory game invented by Mike Zapawa in 2020.

Play Slyde interactively or against AI

  • Group: a set of connected, like-colored pieces on the board.
  • A group's size is the number of pieces that it contains. Pieces come in two states: mobile and fixed. Fixed pieces remain immobile for the rest of the game.
  • To swap: to exchange a mobile piece of one's own with an adjacent mobile piece of the opponent. The swapping player's piece then becomes fixed, the opponent's piece remains mobile.
  • One player owns the white pieces and the other owns the black pieces. The players take turns swapping one piece. White begins.
  • The game ends when no more moves can be made. The player who controls the biggest group (defined by orthogonal connectivity of like-colored pieces) is the winner. If this results in a tie, then second-biggest groups of both players are compared; if that fails too, third-biggest and so on. A draw is only possible when both sets of pieces are partitioned in the same way.

The game starts on a full 12x12 board with pieces alternating in a chessboard pattern. Consider the squares to be the pieces.

Slyde positionIn the diagram White opened with f3-f4 and Black replied with the symmetrical f10-f9. White then played k6-j6 and Black replied with the symmetrical k7-j7. Mirroring strategies can be quite a nuisance, so there’s a special move to discourage them.

  • If a symmetric position arises, the next player to move can choose to change the state (mobile to fixed or vice versa) of any pawn regardless of color instead of performing the standard swap.

So here White instead of swapping could say fix one of the pieces of his 4-group, or 'unfix' f9.

Slyde is a territory game using a somewhat unusual definition of territory. As long as they differ in size, players' territories consists of their largest groups. If these are the same size, then players' territories consists of their largest groups plus their 'next in size' (which may be the same size as the previous one), unless these territories are equal in size too, in which case the groups next in size are considered and so on, till an unequal territorycount results. A very strong incentive to always keep an eye on the overall situation, and not focus on the largest group alone.

Here's an example game between Simon R. (White) and the inventor:
no Sound
Broken canvas...
to move
cascading size
0 0

"Slyde as it should be": Simon R - Mike Zapawa (1-0)

Slyde © Mike Zapawa

In the piece below the inventor describes the invention process:
The creative process of Slyde was peculiar. In most cases, you either start with the mechanics and look for the goal or vice versa. Here, all I had at the beginning was the initial position – one day, after trying and failing to create a checker-like race game, I just thought of a board entirely covered with pawns that alternate in color. What kind of game could be played with such a setup?

Movement by swapping came to me naturally. But there had to be some mechanism to prevent loops – I settled on "fixing" the pawn performing the swap, because it seemed very intuitive. The rationale was that pawns grow "tired" after making an action. This explains one half of the puzzle – why they can’t move. The additional restriction that they can’t be moved provides some measure of finality to each move. Still, the game is semi-impartial, since every swap could be performed by either player.

When performing random swaps, I noticed a trend: on a square board, the number of moves it takes to finish a game is about 0.25-0.35 the size of the board. For instance, an 8x8 board has 64 fields, so the games should last 16-23 moves each. This solidified 12x12 as the smallest board where the game can be expected to have reasonable depth. I was able to calculate that 10^76 is the lower bound for game-tree complexity.

…So now I only had to find the goal. One important feature of Slyde was the visual impression of a highly ordered structure being broken down and reorganized into more chaotic puddles – one chemist I know compared it to the melting process. I determined that the goal should be to have your little puddles as coalesced as possible.

My exact metric of coalescing – the cascading biggest group goal – is controversial. Christian fears it doesn’t give Slyde the strategic depth it deserves. But I didn’t really like any of the alternatives proposed, and playtesting revealed varied strategies – although the game is arguably very unforgiving of blunders.

The discussion of Slyde in the boardgamegeek abstract subforum was animated, but very barren when it comes to actual feedback. Could it be translated to a hex board?, Can you introduce capture? – it soon became clear that most folks didn’t really want to improve Slyde because they saw some flaw in its design. Rather, they just wanted their own Slyde-like game. This was slightly annoying to me, but it helped me see the biggest strength of Slyde – it’s not really a game, it’s an archetype. An inspiring and fruitful one, too! Just like draughts or chess, it takes maybe 10 seconds to introduce a playable and semi-interesting Slyde variant.

The anti-mirroring rule has been added very late in the creative process. While perfect mirroring is impossible, mirrored openings could lead to very frustrating games. The unusual state-swap seeks to provide a formidable anti-symmetric weapon, and is directly inspired by Christian’s Square Off. It lowers the overall organicity of the game, but I hope the muse of boardgames forgives me!