Getting your game ready…
Place a dark stone on an empty intersection of the thirteen-by-thirteen board. You move first; the computer uses cream stones. Tap an intersection, or use arrows and Enter or Space. Five or more of your stones in an unbroken horizontal, vertical or diagonal line wins.
Stones stay where they are placed, and there are no captures. A line can grow from either end, so check a threat in both directions. A completely filled board without a winning line is a draw.
Easy is the starting opponent; choosing Normal starts a fresh board against the stronger opponent. Undo takes back your latest turn together with the computer reply. New game clears the board. Switching away pauses a pending computer turn; Resume continues when you return.
A row with an open space at each end is harder to stop than one pressed against the board edge or an enemy stone. Build connected opportunities while checking whether the computer can complete its own line next.
Before adding to a promising shape, look for four enemy stones that need an immediate block. Then compare moves that threaten two different lines. A move serving both attack and defence can save a turn later.
This version uses freestyle rules: a line longer than five also wins. It does not add forbidden double-threat moves or an opening swap. The smaller board keeps the intersections in view without changing the line-building objective.