Light to move after 19 discs, with 0 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
- forcing sequence — The solution is a series of threats, each one leaving the defence a single answer.
- horizontal four — The four that wins lies flat, along one row.
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.
Before you touch a piece, list every forcing move you have and every threat the opponent has; the answer is almost always on that short list.
Show the first move
Start with d4. Played out against the stiffest resistance, the whole line goes: d4 c4 g2 d5 g3 d6 g4.
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.