The white stone was placed at a point where it would have no liberty if the neighboring black stone were not removed. But by playing that move White captured the black stone, which will have to be removed from the board. Therefore the move was legal.
La piedra blanca se colocó en un punto donde no tendría libertad si no se quitaba la piedra negra vecina. Pero con ese movimiento, las blancas capturaban la piedra negra, que tendrá que ser removida del tablero. El movimiento, por lo tanto, fue legal.