Renju VCF #4996431 (5-move VCF)
To move: Black — find the move that forces a win by fours
Winning line
F8 → F7 → D8 → E8 → J8 → I8 → K7 → M5
Why this move works
The answer is F8. From F8 you fire off fours that force White's replies (F8→F7→D8→E8→J8→I8).
Finally K7 makes two winning points at once; White cannot stop both, and M5 makes five — a five-move VCF.