Connect 4: Better go firstSimple to play though it is, Connect 4 hides a wealth of strategic
detail that’s not a million miles away from complex classics like Go,
draughts, and chess.
So how do you win? There are plenty of good tips out there, including
favoring the advantageous center column, thinking multiple moves ahead,
and stacking your lines one on top of another, so that if your opponent
blocks the lower, you’ll be able to win with the upper.
All helpful advice, but it turns out there’s a much simpler answer.
Just go first.
According to research conducted by Netherlands-based academic Victor
Allis in the 80s, a Connect 4 player who goes first -- and makes no
mistakes -- will always win the game. The correct opening move is right
in the center of the board, as any other opening move can result in the
second player forcing a draw or winning.
“Although many people have seen a ’Connect-Four’ set before, and a lot of them have played the game sometimes,” Allis says in his paper, “very few seem to have encountered at least some of the basic strategics of the game.”
Chief among Allis’s strategic analysis is the idea of the Zugzwang: a
German word often used in chess analysis, meaning “compulsion to make a
move one would rather not.” This happens all the time in Connect 4: if
you want to force your opponent to play a piece somewhere, all you need
to do is fill all the other available spaces.
Allis continued to define a set of nine strategic principles for
optimal Connect 4 play, and programmed a pair of supercomputers to play
through a set of possible iterations from the game’s optimal starting
position. It took over 1000 hours of CPU time to run his tests, although
admittedly that’s 1980s CPUs, which these days would probably look
underpowered in a cellphone. Allis’s work produced a computer program,
VICTOR, which can beat any opponent, human or machine, as long as it
goes first.
So all we have to do to beat our friends is learn the nine rules?
Good luck. Observing that “human intuition is not good enough to really
understand the game,” Allis obviously feels his rules are too complex to
learn by rote -- and we certainly agree.
But there’s one easy(ish) lesson Connect 4 strategists can take from
his work -- aside from his advice to go first, and go in the center
column -- and that’s to count future moves. If you’ve created a pivotal
Zugzwang space -- one where if your opponent was forced to move, you
could then make a winning play -- then count all the other possible
moves on the board.
If the number’s odd, your opponent will be forced to play there
eventually, unless he can win the game by other means first. If it’s
even, you’re the one who’ll have bite the bullet; time to work out an
alternative, quick. That usually means creating another pivotal space to
reduce the pool of possible moves -- just make sure you leave an odd
number on the board.
Alternatively, if you’re more interested in saving face than winning
outright, we suggest going second. If your opponent wins, you can point
out that you were onto a loser from the start -- and if you succeed in
winning or forcing a draw, you’ll know you’ve beaten the odds.
That, or carry a VICTOR in your pocket.