I played this game a while back and thoroughly enjoyed it but forgot the name. It consists of a board, 3 red pieces and a ton of black and white pieces. Each player can move a piece in any straight line in their turn, even onto opponent pieces, but cannot end on an empty space. Stacks are owned by the player with the colour on top of the stack, and each stack can only move the same number of spaces as pieces in the stack. If a piece is not directly connected to one of the red pieces (which I believe have the same name as the game), it is removed from the game. The winner is the player with the largest stack at the end of the game.
Is it dvonn? That seems to fit the bill
DVONN is played on a board with 49 spaces. The board has a hexagonal layout 5 hexes wide. One player has 23 black pieces to play, the other player has 23 white pieces. There are also 3 neutral red pieces, called DVONN pieces.
The game starts with an empty board and proceeds in two phases. During the first phase, the players place their pieces on the board, starting with the three red DVONN pieces. Pieces can be placed on any unoccupied space. White starts, and the players alternate. So Black is the first to place a piece of his own color. The first phase ends when all pieces are placed on the board, filling it completely.
The second phase involves the building of stacks of pieces (a single piece is also considered a stack) by moving stacks onto other stacks. A stack is controlled by a player if his color is on top. A stack is immobile if it is surrounded by 6 neighboring stacks. The white player has the first move in this phase. Any mobile stack of height n (with n > 0) can be moved (in a straight line) in any one of the 6 directions by exactly n spaces by the player controlling it, if it lands on another stack. Jumping over empty spaces is allowed, as long as the tower does not land on an empty space. Single DVONN pieces cannot be moved, but they can be once they are part of a stack. After each move, all stacks that are not connected via a chain of neighboring stacks to any stack containing a DVONN piece are removed from the board.