Parity in the Othello Endgame: Get the Last Move
In the last moves of a game, the discs you flip often get flipped straight back, and the player who moves last in an area keeps what they flip. Parity is the idea that helps you be that player.
Step 1 of 3
Regions
Near the end, the empty squares fall into regions: groups of empty squares that touch. Here there are three, starred: six squares in the bottom-left corner, g1 on its own, and h7 on its own. If the two players take turns inside a region, the player who moves first into a region with an odd number of squares also moves there last. That is parity: when you can, play into a region with an odd number of empty squares.
Play the odd region
The move that flips the most here is d2, six discs. g1 flips two. (h7 is an odd region too, but you have no move there.)
Your move
Play into a region with an odd number of empty squares.
Two moves, one choice
Black has two moves. e1 flips four discs, and h7 flips one. Which one does parity pick?
What you learned
- Near the end, the empty squares form regions.
- In a region with an odd number of squares, the player who moves there first can also move there last.
- Play into odd regions, and leave your opponent the even ones.
In this course
Unit 1The rules
Unit 2Strategy
Take it to the table.
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