What is your opinion on size of board ?

I think it would be better on an 8x8 board, simply because it's standard chess board size and easier to practice on.

I agree with Barry

Apparently the original size was 7x7, and then the inventor changed it to 8x8, so that it could compete in the game design competition. There may have been a good reason why the original size was 7x7. The pieces move slowly, and on the 8x8 board it takes a long time for enemy pieces to reach each other. Although it is difficult to judge without playing many games, I think this would be an advantage with the smaller board.

I agree with Taral.

How about 8x7? :) eight pieces each, but 7-square width. It will take less time to finish a game. But an 8x8 board is very nice. I am having fun.

I am beginning to change my mind about the opening. Just because I can't see it, doesn't mean there isn't a lot going on.

I'm concerned about the possibility of cheating with the Zillions Breakthrough package, and I thought maybe 9x9 would be better because Zillions goes up to only 8x8. But users could easily modify the files to make any size board. Zillions doesn't play the whole board well, but it can see endgame tactics if you give it time. FWIW I will never use it this way during a game.

The board size doesn't necessarily have to be square. Other board sizes to consider are 6x9, 6x10, 7x9 and 7x10. To explain why I think so requires a quick story.

A game by the name of Evade, which was produced by the 3M Corporation in the early 1970s, can probably be considered a cousin to Breakthrough. You can read a litte bit about Evade (among other places) at the BoardGameGeek website.

http://www.boardgamegeek.com/game/1735

The object of Evade is to move what I believe was referred to as a “Runner” to the last rank. Each player has two Runners and four “Blockers.” The identity of each was not known to the opponent. (Thus, Evade was not a true abstract strategy game… since it was not a game of perfect information.) Blockers could take out and neutralize other pieces. After doing so, the Blocker was also neutralized and could not move again for the rest of the game.

Again, the game was won only if a Runner reached the last rank. Note that Runners could NOT neutralize other pieces.

Anyway, when I was much younger, an old high school chum and I used to play Evade quite a bit, but after awhile we didn't like the constraints of the tiny 6x6 board. (We also didn't like the pieces… both were much too small and in poor light the gold pices were actually hard to distinguish from the silver pieces.) So, we ended up using Stratego pieces instead and made up our own board.

We thought the board size could be improved upon if we expanded the playing field, giving us more room to manuever. But we didn't expand the length, we expanded the width. (Giving the board more files, not ranks, if I could coin a chess term.) After much experimentation, I think we ended up with a board that was 7x9 or 7x10 or 6x10 or something very similar. (Again, the smaller number is the number of ranks.) This new board size gave us room to manuever from left to right, yet the action was still fast and furious.

I agree with Taral's comment that the pieces in Breakthrough do take awhile to come in contact with each other. Less ranks would change that, but I also agree that just because pieces take a long time to come in contact, doesn't mean that things aren't going on, and there isn't room for much strategy during this opening phase.

About “Evade” it is apparently based on an earlier 3M game “Breakthru”!

About board size with wider boards you have to consider one strategic implication: a piece in the left corner can no longer cross the whole board to win in the right corner. On a shorter board every piece gets a reduced influence…

For comparison, we can look at the closest widely played game, which would be checkers. Traditional checkers is played on either 8x8 or 10x10, with only half the squares in actual use, so that corresponds to 32 and 50 play spaces, respectively. The 32 size one is suffering from very real draw death, while the 50 size one is working just fine. A 7x7 breakthrough board is 49 play spaces, just one less than a 10x10 checkers board, indicating that it's plenty big enough.

Strategically, while I haven't played 7x7, I have noticed that the 8x8 tends to get bogged down in both players not wanting to cross the center line, because that puts them behind in advancement. The 7x7, however, is likely to have a very early battle for central places, because getting those traded off is neutral for advancement.

Also, it's my observation that while the opening of a breakthrough game on 8x8 isn't all that long, it does mostly come off as meaningless wood-pushing.

So in summary, I think that the 7x7 is plenty big enough, has some interesting strategic elements not present on the 8x8, and would help get the game going faster in the beginning. I'm in favor of making it the standard, although would like to play-test it a bit before that happens.