Corner opening (0). Theoretically slightly weaker than center (3 lines vs 4), but practically harder to defend — only ONE drawing response exists for O: the center. Any other O reply (another corner or any edge) lets X force a fork and win. Testing whether Gemini 2.5 Pro knows the corner-opening defense.

The only non-losing response to a corner opening is to take the center. Any other move allows the first player to force a fork and guarantee a win.

Opposite corner (8). Standard continuation in the corner-vs-center line. Now O must play an edge to draw — playing another corner (2 or 6) lets X fork by occupying the remaining corner. Testing whether Gemini Pro knows this second-level theory.

The opponent is correct; playing a corner (like 2 or 6) would allow X to take the last corner and create an unstoppable fork. To prevent this and force a draw, I must play on an edge square, all of which are strategically equivalent at this stage.

Forced block on column 1 (O has 1+4, would win at 7). Bonus: this same move creates my own threat on row 2 (6-7-8 with X at 7+8, needing 6). Dual-purpose: blocks O's win + forces O to defend my new threat.

The opponent's last move created an immediate winning threat on the bottom row with positions 7 and 8. I must play position 6 to block this line and prevent a loss, as any other move would result in my defeat on the next turn.

Forced block on the anti-diagonal (O has 4+6, would win at 2). Same move creates my col 2 threat (X at 2+8, needs 5). The position is tightly mutual: I block O's only winning line while opening my own. From here it's a forced 3-move sequence to a draw.

The opponent has a winning threat on the rightmost column with pieces at positions 2 and 8. My only valid move is to play position 5 to block this line and prevent an immediate loss, thereby forcing the game to a draw.