Bluestone is played by placing black and whites stones on a special pentagonal grid marked by "blue stones" on the perimeter. The goal is to connect to as many blue stones as you can using your own playing stones.
BLUESTONE RULES
Placement: The first player on turn 1 places a single stone into any empty cell. Thereafter, starting with turn 1 for the second player, each player on his/her turn places two stones into empty cells, with the following restriction: the second stone may not be placed into a group that contains the first stone. (If it is impossible to place the second stone in a different group, then that stone is forfeited.)
Group score: A group of connected same-color stones has a score equal to the number of blue stones it connects to
Capture: If a group is surrounded by an enemy group in way that makes it impossible for it to connect to at least FOUR blue stones, then that group is captured.
Winning: Play continues until the board is full or both players pass in succession. At that point, the player with the highest scoring single group wins. If both players' highest scoring groups are equal in score, then the players look to their remaining groups; the player with the highest scoring single group from among these remaining groups wins. If there is still a tie, then players keep comparing their highest scoring groups "down the line" until the tie is broken. (It is impossible for group scores to be tied "all down the line.")
Final Scoring Example: Player A ends the game with groups scoring 10, 8, and 5; Player B ends the game with groups scoring 10, 8, 4, and 4. The players' first-highest and second-highest scoring groups are tied at 10 and 8 respectively. Player A wins the game with his/her third-highest scoring group, since this group scores 5 for A compared to 4 for B. (Note that the total score of all of a player's groups summed together -- in this case, 23 for A and 26 for B -- is irrelevant.)
—description from the designer