Othel Lehto is a strategy game of perfect information for two players.

Needed

• A square game board with an odd number of squares per side (at least 7x7 recommended)
• Enough Reversi pieces to fill the chosen board

Goal

The player with the most pieces with their color turned up wins the game.

Game play

The first player plays a black piece onto any square. The second player may choose to either place a white piece onto any other square or switch colors with the first player. Play then proceeds as follows:

• Players place one piece per turn onto any unoccupied square.
• If the placement forms a palindrome with any connected pieces side-to-side, up-and-down, or diagonal, bounded by empty squares or the edges then all of the pieces in the palindrome are flipped to the color played.
• If a flip causes the formation of another palindrome then the new palindrome is also flipped, if that too forms a palindrome then it too is flipped, and so forth.

Forming palindromes

Palindromes, must be bounded by the board edge or empty spaces. Therefore, white can play at any of the positions below to form a palindrome:

However, none of the placements below form a palindrome:

Forming a palindrome, may trigger the formation of other palindromes. Below white places a piece to form a palindrome:

The palindromic flip then forms another palindrome:

Which is also flipped to white:

Since no more palindromes can be formed white's turn ends.

End

When the board is filled or the players mutually agree then the game ends and the score calculated.

Othel Lehto is © 2015 by Fogus.