Renju VCF #4996510 (7-move VCF)
To move: Black — find the move that forces a win by fours
Winning line
G9 → H9 → E7 → H10 → D6 → C5 → F6 → C6 → E5 → G7 → E4 → E3
Why this move works
The answer is G9. A seven-move VCF that drives White with a four every move (G9→H9→E7→H10→D6→C5→F6→C6→E5→G7).
The decisive E4 makes two winning points at once; White cannot cover both, and E3 makes five.