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Gomoku lessons · Intermediate · Step 7
Double Three (3-3)
Making two open threes with one move is called a double three (3-3). While your opponent blocks one, the other becomes an open four. (In real games, a 3-3 is a forbidden move for Black. It's allowed here so you can learn the shape. You still need to know it, because you have to stop White's 3-3. The standard way for Black to win is with a 4-3, which isn't forbidden.)
Puzzle 1
Where can you make two open threes? (Black to move)
Show answer and explanation
The green circle marks the answer. Open threes appear horizontally and vertically at the same time. Whichever one White blocks, the other becomes an open four.