X-Squares and C-Squares in Othello
Corners can never be flipped, so the way to lose one is to open the door to it yourself. The usual door is a disc on one of the three squares beside an empty corner.
Step 1 of 4
The squares beside a corner
The stars mark the three squares beside the empty corner a8. The one diagonally next to it, b7, is the X-square. The two beside it along the edges, a7 and b8, are the C-squares. Every corner has one X-square and two C-squares. A disc there while the corner is empty can give your opponent a disc to flip on the way into the corner.
Keep off the X-square
The move that flips the most here is b7, the X-square: it turns over three discs. Before you play it, look at what White could do next.
Your move
Make a move that doesn't give White a corner.
Careful with C-squares
Here the move that flips the most is b8, again three discs. b8 is a C-square, on the top edge next to the empty a8.
Your move
Make a move that doesn't give White a corner.
Your own corner
g8 is a C-square too, right beside h8. Does playing it give White a corner?
What you learned
- Each corner has an X-square diagonally next to it and two C-squares beside it on the edges.
- While a corner is empty, a disc on those squares can hand it to your opponent.
- Next to a corner you already own, they give nothing away.
In this course
Unit 1The rules
Take it to the table.
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