Renju VCF #4996343 (3-move VCF)
To move: Black — find the move that forces a win by fours
Winning line
J5 → J7 → I6 → K4
Why this move works
The answer is J5. The four forces White to block at J7.
Then I6 makes two winning points at once. White cannot cover both, and K4 completes five — a textbook continuous-four finish.