Light to move after 21 discs, with 2 columns already full.
Connect four within 4 of your own moves. Exactly one column starts the win; any other lets the opponent off.
What the position is about
- quiet move — The key move threatens nothing directly; it prepares a threat that cannot be met.
- vertical four — The winning line runs straight up a column.
Finding the way in
In four-move wins, track which spaces become playable after each forced block; the final double threat often appears two rows above where you start.
Play the position in your head from the opponent's side: what would you do against your favourite move? If there is a good answer, try the next candidate.
Show the first move
Start with b3. Played out against the stiffest resistance, the whole line goes: b3 e6 f2 b4 f3 b5 f4.
Solve it and the next puzzle of the same game is one tap away. Your solved puzzles are ticked in the list, in this browser only.