Sum On is an abstract strategy game of clever move chaining, for two players. You must use both your pieces and your opponent’s pieces to make bonus moves, so step wisely!
Your pieces are numbered 1–8. On your turn, you move one of your pieces one step orthogonally or diagonally forward. Then, look for a bonus move: Choose an axis through that piece, and sum the values of all pieces along that axis (including the one you moved, any of yours, and any of your opponent's!). Now you get to move your piece whose number matches that sum, and so on until you've run out of bonus moves. Finally, it's your opponent's turn.
The game ends when someone cannot make their opening move for the turn. Each player sums the values of their pieces that made it all the way to the other side; higher sum wins!
The rules also offer two variants, which means there are 4 ways to play the game!
—description from the publisher