Opening Theory

Although the starting position in crumble resembles an empty chess board, the position is anything but quiet. Every piece on both sides starts off locked in battle with its neighboring pieces. Every move is an attack into the very heart of your opponent’s game.

Local Battles

Consider crumble as a game of local battles. In the endgame, the local battles have all become very local, to the point where their outcomes are mostly predictable, and it’s generally possible to say which player has the advantage.

In the very opening then, the “local battle” is the whole game board, and there is only one battle on the field. It is only as each move is played that certain parts of the position become isolated from other parts, and the number of distinct local battles increases.

So one aspect of the opening, therefore, is the attempt to define smaller regions of the board, where you believe you would have the advantage, or at least equality. Just as in the Japanese game of go, where placing a single stone stakes out a claim over a larger region of the playing field, so in crumble a single split stakes out a claim as well.

Subsequent moves then further subdivide these regions, attempting to isolate more and more local battles favorable to yourself.

Chain Building

The opening also involves, to one extent or another, an attempt to extend a chain of your own pieces across the board, in order to win by touching all four sides of the board with a single chain.

Your strategy may involve building long chains quickly, or it may involve preventing your opponent from building them.

The value of a long chain of pieces is that you can start to combine threats to win with other threats, such as to capture pieces or create impervious or redundant pieces.

On the flip side, the value of preventing long chains of pieces is that it keeps the position fluid and open. In general, when both sides continually threaten to win on each turn, each player may find their options severely limited for the long term.

Imperviousness And The Center

Another goal of the opening is to try to establish impervious pieces, as close to the center of the board as possible. These can give a long-term structural advantage to your position. Likewise, preventing your opponent from establishing impervious pieces is a significant goal in the opening.

It is generally not possible to simply make a piece impervious. It requires a minimum of four moves — one for each side of that piece — and your opponent won’t be sitting still while you do that. The types of battles involved in piece imperviousness are central to the whole theory of crumble.

But for example, consider a player who intentionally doesn’t try to make any piece impervious until, through the normal course of play, they notice that a given piece already has two impervious sides. At that point the idea would suggest itself, to split a piece touching the third side, and swap it somewhere that will initiate a strong threat. If the opponent responds to that faraway threat, then the player can use their next turn to render the fourth side of their target piece impervious as well.

Material Balance

Splits and swaps in the opening tend to involve starting-sized pieces, so they are opportunities to quickly build up a sizeable lead in material — or more realistically, to maintain material equality.

In the late opening and middle game, pieces tend to be a lot smaller, and you gain less material by occupying them. So it becomes harder to shift the material balance in one direction or the other, and therefore the shifts in material balance that happen in the early opening tend to become cemented as the game proceeds.

Putting It All Together

The starting position in crumble is so active while at the same time so uniform, that it can be bewildering to try to decide on any opening moves.

In the absence of direct threats and clear plans, it can be tempting to make opening moves at random.

In fact, there is a combination of motivating features in the opening: dividing the board into regions that favor you; building chains; establishing a foothold in the center; maintaining the material balance. And taking advantage of opportunities to make concrete threats that can gain time by diverting your opponent from what you’re really trying to accomplish.