Puzzle #4

Solution: drop in column 6

Counting columns from the left and rows from the bottom, red plays column 6. That single drop creates two winning squares at once: column 4 on row 3, and column 6 on row 4.

• If blue blocks column 4, red wins in column 6.
• If blue blocks column 6, red wins in column 4.
• If blue plays anywhere else, red takes either square and wins at once.

This is the double threat from our strategy guide: one move, two winning squares.