Five in a row

Rules

Dark places the first stone, then the players alternate, one stone per turn on any empty intersection. Stones never move or leave the board. With the free rule, five or more in a straight line win. With the exact rule only exactly five counts, and a line of six or longer does not win. Choose the rule in the table settings.

The language of threats

• A four is a line of four with an empty end: your opponent must block it at once.
• An open four has both ends empty and cannot be stopped.
• An open three, three in a row with room on both sides, becomes an open four next move, so it must also be answered.
• A double threat, such as a four and an open three made by one stone, wins because only one of them can be blocked.
• A chain of fours, each forcing a block, can lead to a winning double threat. Strong players calculate such chains first.

Opening and middle game

• Keep the first stones close together near the centre. A compact group creates more potential lines than scattered stones.
• Defend by building when you can. A block that also starts a line of your own gains a tempo instead of losing one.
• When your opponent has an open three, you may block either end, or the gap if there is one. Choose the block that also helps your own shape.
• Count before you push. A four that is simply blocked only helps if the block costs your opponent something.

What goes wrong

• Answering every three passively. Sometimes the right reply is your own four, which forces your opponent to answer you instead.
• Building lines that are already blocked at one end. A three closed on one side is much weaker than it looks.
• Playing far from the action. Stones away from the main group rarely help either attack or defence.

The computer at this table

The Champion first looks for a forced win by continuous fours and then checks that its move does not allow you one. The first player has a real advantage in this game, so try both sides.