Piece "1" is your king, keep it safe and kill opponent's "1" to win.
The piece walks exactly(not less than) x steps, x is its number.
A step is a move form your current box to on of the neighbor boxes(left, right, up or down).
When the middle of the walk path stands a friend piece or enemy piece, this path is invalid, you can not walk though that way.
When the end of the walk path stands an enemy, enemy will be killed, no matter what number it is(that means your "2" can kill enemy's "3" althought 3 is bigger than 2).
You can not walk back to the position already visited in one movement.
This game was invented in 2000 when I was 13 year's old.
The first version is 12 cutted erasers on paper.
Finaly I put it online and play it with my old friend thousand miles away, super happy :D