Thanks a lot to Alan Hensel who allowed me to publish his following article here!

There is probably no "Grand Unified Theory" of opening moves in Twixt. I use a combination of three loosely-knit theories: blocks, balance, and potential paths.

Blocks: A block is simply anything between your opponent and his side, mainly within the isosceles triangle with sides of slope 1/2. You do have to learn the best gaps, when to use them, and how they can be circumvented.

Also, don't block yourself! That may seem like an obvious thing to say, but I sometimes see people (not in the top 10) trying to follow the "dipper" formation (example, done right:)



and they put that 5th peg where it's already blocked by their opponent (in the above example, imagine 5.o14, or even 5.p14, instead. Both would be blunders. It may still look like the right pattern, but it's not.)

Balance: This is a more subtle concept. Let me begin with a hypothetical question:

Suppose you were playing without the pie rule. What would be the strongest first move? (Normalize to the upper left quadrant).

The rookie answer is "L12" (in the middle of the board). It is also the wrong answer.

I don't know the exact right answer, but my guess would be H12, or nearby. Why? Balance... That is, balance for yourself, and not for your opponent.

Balance for yourself means that row 12 is probably correct, because it splits the board most evenly in half. In other words, why give your opponent a 60:40 choice when you can give him a 51:49? If you give him 60:40, he'll probably take the 60.

But that says nothing about what column is correct. Look one move ahead at L12: a simple block, L16, splits your next choice evenly.


In other words, you've made it easy for your opponent to make a balanced move. If you start off-center a bit, say, as far left as H12 or as far right as Q12, your opponent will have a harder time finding balance. He'll actually be forced to choose between blocking and balance. And he almost has to choose blocking, leaving the board unbalanced, and yourself in a better position.

It may seem counterintuitive, but dominating the center of the board is not as relevant in Twixt as it is in other abstract games. Many final paths in Twixt run along a side. But don't make the opposite mistake, either: you should not specifically try to build your line along the side. You should spread your threats over the board, and let the circumstances dictate where your final line will go. A newbie that runs his line up the side against a strong player will have his line lightly pressed with the weakest threats that work, until his line is finally cut off, and the strong player will then have built a wall that effectively shortens the board in his own direction, while leaving the newbie to cross the entire distance again.



The influence of the first peg under the pie rule is that it unbalances the board. A corner opening (c3, d3, e3, f3, g4) will draw the H12-equivalent L8 over to somewhere around j10, for example. Or, the Q12-equivalent L17 over to about k15.

Note: the "Klaus opening", (d3/e3) o10, defies the principle of balance. Much of the strength of that opening is in following the strategy of committing your opponent to a line, and then cutting it off. But don't worry about advanced openings until you've mastered the basics.

Next question: How many moves into the game does balance apply?

A beginner may guess 1 or 2, but in fact, the principle of balance can guide your thoughts through the "dipper" formation and beyond, sometimes as many as 10 moves into the game. Sometimes you can use the idea of balance later in the game, especially if there is still an empty region of the board that has suddenly become important.

Potential Paths: The idea is simple: look for the strongest threats of forming lines across the board. This kind of thinking may start when you or your opponent have as few as 3 pegs on the board.

When looking for the potential paths, you often find a "Y" formation (albeit usually a very misshapen "Y"). Seeing this can be tricky, especially with as few as 3 pegs, since tracing the path of the Y shape depends on common sense, logic, and experience. You have to have a sense of which pegs can connect to the edge, whether a corner battle looks winnable, and how vulnerable the gaps are. Sometimes, with 3 pegs, what looks like a "/" shape is actually a "Y", or what looks like a "Y" at first doesn't really work.

Recognizing potential paths is important because it can give you hints about the best area of the board in which to play. Usually, with a "Y" formation, the best response is between the upper branches of the "Y", making both branches hard to complete. The interesting thing is that this typically creates your own "Y" shape, 90 degrees rotated. Sometimes, if the stem of your opponent's "Y" is weak, you can try to cut that off instead. On other occasions, it is best to attack the center of the "Y".

If your opponent forms an "H" or "X" shape, treat it like a double-headed "Y": attack above the upper or below the lower branches, making both paths hard to complete. Or attack the middle: an "H" shape without its middle is just two lines; then, your defensive task is to make neither line work.

Sometimes, if you have an overly aggressive opening, you may be stuck defending a single line during the whole game. This is dangerous. It is generally a good principle to form double threats, and best if the double threats are spread apart. A "Y" formation is a spread double threat. During the opening moves, it is especially easy and tempting to create a local battle too early, and forget the big picture. Avoid that temptation. Play the whole board.