Click the board to let Zillions create a random setup of black and white stones (225 stones on the 15x15 board).

Switch on Smart Moves (View/Options/Board/SmartMoves).
You remove (orthogonal or diagonal) rows of five consecutive stones. (later in the game also 4-in-a-row, 3-in-a-row and 2-in-a-row, see below).
You do this by moving a stone from one position to a position four units away.
With Smart Moves switched on this means you usually only have to click the starting position of this move.

After each move, the stones above empty positions will drop down.
Also, tokens whose southeast or southwest position is empty will slide to this southeast or southwest position.
This 'avalanche' automatically continues until no dropping or sliding is possible.

Once there are less than 100 stones left on the board, you are allowed to remove 4-in-a-row collections of stones.
Once there are less than 50 stones left on the board, you are allowed to remove 3-in-a-row collections of stones.
Once there are less than 30 stones left on the board, you are allowed to remove 2-in-a-row collections of stones.
Signs '4','3' and '2' at the right border will remind you of these additional moves.

You win when you have removed all stones from the board.
Experts: Try to solve the puzzle without using the 2-in-a-row option.

Variant 2:
Here you play on a 19x19 board.

Hint: hit function key F7 to see where you can go.

Please note that there are three piece sets available.

 
The idea in this game is opposite to the one in the game Go-Moku. Instead of building 5-in-a-row here you remove 5-in-a-row arrangements.