Connect6 Rulebook

Table of Contents

Table of Contents

• Players
• How to Play
• Board
• Proposed Rule Extensions
  • Proposal: Enlarge the board to 59 lines
  • Proposal: Break ties by counting lines of five, then four
  • Proposal: Claimed draws
  • Proposal: Pie-style opening protocol
• Etiquette

Players

As in Gomoku and Go, there are two players, Black and White, each holding stones of their own color. Black plays first.

How to Play

Except for Black's first move, in which Black plays only one stone, Black and White alternately place two stones per turn. The first player to form an unbroken line of six or more stones — horizontally, vertically, or diagonally — wins.

If the board fills completely without either side winning, the game is a draw.

There are no forbidden moves; for example, an overline (more than six stones in a row) still counts as a win.

Note: Renju rules and international Gomoku rules include additional forbidden-move and opening restrictions. Connect6 needs none of these.

Board

Because fairness is not an issue, the board may be of any size, even infinite. However, to make the game practical to play, the board currently used is the 19-line Go board.

Proposed Rule Extensions

For ordinary players, the original rules above are already sufficient. However, after several tournaments, some high-level players raised the following issues for consideration.

Most top Connect6 players currently play on the 19-line board. Although draws are not yet frequent, many high-level players believe, based on their research, that Connect6 is quite possibly a drawn game. The problem with a drawn game is that too many draws make it less interesting. Judging by the current experience of some gaming websites, this may not yet be a problem, but it could become one in the future.

After both sides together have played more than 100 moves, if it is already clear that neither side has a winning line, the game is very likely a draw. However, under the current rule the players must fill the entire board before a draw can be declared; if one side insists on playing it out, this can become tedious.

Currently, in tournaments, high-level players tend to prefer playing White, because the player with White can choose an opening they are familiar with. This means a player could focus their study on only one style of White play, which risks narrowing research into and development of Connect6. (Of course, the issue of studying a fixed opening also arises in other games such as international Renju.)

For these reasons, sometime after a year or two (around 2008), the rules of Connect6 will likely need to be extended or adjusted. However, to avoid the problems international Renju encountered when its rules were revised in the past, the organization hopes players will study and discuss these extended rules carefully, so that they can be settled once and for all — ideally remaining unchanged for a hundred years. The proposals below were on the table at the time of writing; none of them is an adopted rule.

Proposal: Enlarge the board to 59 lines

Since, in theory, Connect6 on an infinitely large board remains potentially fair and intuitively fair, the board may be of any size, even infinite. Extending this idea, the board can be expanded to a 59-line board. Professional players could play the 59-line board using a computer; without a computer, it could also be played by joining 3x3 Go boards together. Because the joining lines also count as board lines, these nine boards together form one large 59x59 board. In actual play, the game should begin on one 19-line Go board, and only when play extends beyond it should the additional boards be joined on.

• Proposed by: Professor I-Chen Wu and others.
• Purpose: solves the first problem (possible frequent draws).
• Drawback: the second problem (tedious forced completion) may become more severe, and playing on such a large board for so long is not practical for actual tournaments. For this reason, Professor Wu and others have already abandoned this proposal for tournament use; it may only be suitable for academic research.

Proposal: Break ties by counting lines of five, then four

If neither side has formed a line of six, the winner is decided by whichever side has more lines of five; if the number of lines of five is also equal, by whichever side has more lines of four, and so on.

• Proposed by: Li Shih-Wen (nickname: "Killer Wen").
• Purpose: solves both the first and second problems. This rule would prevent high-level players from frequently drawing (even though this is not yet common), and, much as a Go game must still be scored point by point at the end, would require players to carefully contest the number of lines of five (while also preventing the opponent from completing a line of six). It is expected that contesting fives would also give rise to new playing techniques.
• Drawback: counting down to lines of four or three would become very complicated. A possible simplification is to count only as far as five.

Proposal: Claimed draws

When one side (A) claims a draw, if the other side (B) does not agree, A may forfeit part of their turn (playing one stone instead of two, or none at all); if B still cannot win, A is ruled the winner.

• Proposed by: You Chih-Hsiang (nickname: "CHY").
• Purpose: solves the second problem. This method allows a draw to be settled early, but it still does not solve the first problem.

Proposal: Pie-style opening protocol

Modify the opening rule as follows. The first five stones (one Black, two White, two Black) are placed one at a time, alternating between the two players, as follows:

1. The provisional first player ("pre-first") places the first Black stone.
2. The provisional second player ("pre-second") places the first White stone.
3. The provisional first player places the second White stone.
4. The provisional second player places the second Black stone.
5. Finally, the provisional first player places the third Black stone.

However, whichever side's turn it is may instead choose to pass, handing the choice of that stone to the opponent (the player who placed the previous stone). Note: the opponent may not also pass, since the previous stone was chosen by them and they must take responsibility for it. Whichever side did not place the fifth stone then decides whether to play Black or White.

• Proposed by: Li Shih-Wen (nickname: "Killer Wen").
• Purpose: solves the third problem (color/opening preference). According to Killer Wen, this method can, in fact, also solve the corresponding problem in Renju.
• Drawback: the rule becomes too complicated. It is therefore suitable only for professional tournament play.

These proposals were not finalized: Connect6 had at the time been publicly developed for only a little over a year, and many high-level players still felt the game was not yet sufficiently understood. The Taiwan Connect6 Association reserved the final decision on whether to adopt any extended rule.

Etiquette

In principle, Connect6 etiquette is largely the same as in Go; only the differences are listed here.

Because one distinctive feature of Connect6 is that each turn places two stones, care should be taken not to take too long between placing the two stones. Most importantly, once a stone has been placed, taking it back is strictly forbidden. Many computer programs permit this because the placed stone has not yet been transmitted to the other player; however, in an actual face-to-face game, taking back a move after placing a stone is strictly forbidden under any circumstance.

Black's first stone should be placed on the board's tengen point (the center point of the board), as a sign of respect toward the opponent.