A race of threats
Five in a Row, also called Gomoku, is played here with freestyle rules on a 15 by 15 board. Any line of five or more wins, and no moves are forbidden. You play black and always move first, which is a real edge in this form of the game. The trick is turning that edge into a win before the computer's own threats catch up with you.
Most games aren't decided by who builds the longest line. They're decided by who first makes a threat the other side can't answer in one move.
The shapes worth knowing
- Open three. Three in a row with an empty crossing at both ends. If it isn't blocked, it becomes an open four next turn.
- Split three. Two stones, a gap, then one more stone, with both ends open. It's just as dangerous as an open three and much easier to miss.
- Four. Four stones that need one more to make five. The other side must block at once.
- Open four. Four stones with both ends open. It can't be stopped, because there are two winning crossings and only one block.
- Four-three. One stone that makes a four and an open three at the same time. Your opponent blocks the four, then the three becomes an open four. This fork is the most common way games are won.
Building a winning attack
Start near the centre. The crossing marked by the middle star point gives you room in every direction. Stones near the edge have lines that run out of space.
Grow your stones loosely. Put them a crossing or two apart on several lines at once, rather than in one long row. Two stones that share a crossing on two different lines are worth more than three in a straight row the computer can see coming.
Here is a worked example. You have stones on a row with one crossing empty between them, so the pattern reads stone, gap, stone. You also have two stones on a diagonal that passes through that gap. Now place a stone on the gap. The row becomes a solid three, and the diagonal becomes a three as well. If both are open at their ends, you've made two open threes in one move. The computer can block only one, and the other grows into an open four.
Fours can also drive an attack. Each four forces an immediate block, so a string of fours keeps the computer busy while you move your stones into place. Players call a win made only of fours a victory by continuous fours. Look for one whenever you have several twos and threes near each other.
Defending well
- Block open threes early. Once an open three becomes an open four, the game is over. Block a three as soon as it's open, and look for split threes too.
- Block on the side with more room. If an open three has space to grow at one end and is near the edge or your stone at the other, block the roomy end.
- Defend with a move that also builds. A block that also extends one of your own lines keeps you in the race. A purely passive block often hands the computer the next free move.
- Count before you attack. If the computer has a four-three ready, your own open three is too slow. Stop its threat first.
Playing with Captures
Switch the Rules setting to Captures and every pair of stones becomes a target. Flank exactly two enemy stones with the stone you place and they come off the board; five pairs also wins. Three habits matter most:
- Count twos, not just lines. Two of your stones side by side with a white stone at one end can be taken next move. A single stone or a solid three can't.
- Break lines by capturing. Taking two stones out of the computer's four is a block that also scores.
- Watch the pair count. Once either side has four pairs, every capture threat is as urgent as an open four.
Practising with the three levels
Easy plays the best-looking move without reading ahead, and varies its choices. Use it to practise making open threes and four-threes and to learn to see them quickly. Medium reads two moves ahead and will block most single threats, so you'll need double threats to win. Hard reads four moves ahead over its strongest options. It sets up forks of its own, so your defence must be as sharp as your attack.
A good drill is to replay a lost game in your head. Find the move where the computer made a double threat, then go back two or three moves and find the crossing that would have stopped it. If you like this kind of line building, Four in a Row uses the same ideas with gravity added.
