Placing first in a swap variant: do not place the black pieces within 7 spaces of each other unless they are closer than 3 spaces to the edge.
To swap or not: if you have the choice, then take black unless the black pieces are more than 7 spaces apart or they are closer than 3 spaces to the edge.
Generally, a strong defense is critical; never leave an open-2-in-a-row or any 3-in-a-row alone. Strive to deny your opponent any opportunity to build up. A wise person once said, "Don't lose". You cannot win if you lose.
Playing pieces (in priority order, i.e. timing is everything!)
- finish a 5-in-a-row (search exhaustively)
- (optional) either explicitly concede or implicitly concede gracefully by playing away if your opponent has
- an open-at-the-ends 4-in-a-row
- two open-at-one-end 4-in-a-rows
- block an open 4-in-a-row (usually just formed)
- make an open 4-in-a-row or two 4-in-a-rows
- if you think you might have a forced win, double and triple check it before pursuing it, e.g. make a 4-in-a-row that leads to your forced win, etc.
- take into account your opponents plays in case they form a threat
- block an open 3-in-a-row (both "xxx" *and* "xx x") (usually just formed)
- with strong offense: (rare) block forming a pair of open 3-in-a-rows (don't miss the more subtle "xx x" configurations)
- assess your opponent's next possible move (two with "xxx" or three with "xx x")
- block where your opponent's move would give them a forced win
- assess overall game situation
- if they are strong in this part of the board then block where your opponent's move would give them a significant advantage
- if you are strong in this part of the board then block where placed stone "sees" other of your stones
- combine offense and defense: play where you get both open 2-in-a-row(s) and block open 2-in-a-row(s)
- work to overwhelm your opponent in some part of the board
- look for a forced win; be sure it is real; once you're sure then pull the trigger
- delay playing non-open 4-in-a-rows until you have a forced win
- delay playing 3-in-a-rows in favor of a forced win
- if you can't find a forced win then maybe an open 3-in-a-row can help build command in an area but it is often better to delay these
- avoid letting your opponent have too many stones in one area
- divide your opponent's pieces
- place a stone exactly 5 spaces away from another your stones; your opponent will waste stones in between them