Shello

from the designer's site:

Shello is a game for 2 players, played with chips that are white on one side and black on the other, on a 9×9 square grid (or larger, as long as there are an odd number of cells in the grid. But 9×9 is all you’ll need for a long time.)

The game starts with a set board layout.

The pieces in the corners are called Neutral Pieces. These count as both black and white. They never move and they’re never flipped, but they can be used to flip pieces of either color during the game.

Rules

1. One player plays pieces black side up, and the other plays them white side up. Starting with Black, the players take turns. On your turn you must either: A) place a piece on an empty space orthogonally-adjacent to any friendly piece, or B) move any friendly piece, by a chess queen’s move, to any empty space not orthogonally adjacent to any friendly pieces.

2. If you have no legal moves, you must pass.

3. After placing or moving a piece, flip all enemy pieces lying in an uninterrupted straight orthogonal or diagonal row between the piece you placed or moved and any friendly pieces.

4. The game ends when the board is full. The player with more pieces on the board wins.