Copyright (c) 2001 Kris Burm

DVONN is played on the following initially empty hexagonal board. 
Each player has 23 stones and there are also 3 DVONN stones  (herein, red stones).

PHASE 1 - First player places a DVONN stone on an empty cell. Second player places a DVONN stone on an empty cell. First player places the last DVONN stone on an empty cell. 
PHASE 2 - On each turn, each player places a stone on an empty cell. The second player starts this phase.
PHASE 3 - When all stones are dropped, the first player starts phase 3. So, he will drop the last stone of phase 2 and starts moving..
On each turn, each player move a stack that he owns (a stone is a stack of size 1).
A stack belongs to the player that has the stack's top stone.
A stack of size N may move exactly N cells in a straight line to an adjacent non-empty cell. The stack goes to the top of the stone/stack of either color.
Even if the stack cannot move into an empty cell, it may cross empty cells during its move.
A stack surrounded by all sides cannot move!
A DVONN stone cannot be moved by itself, but a stack may move on the top of it and move afterwards with all its stones (and so, moving the DVONN).
Passes are only allowed if the player cannot move.
REMOVAL - After each move, any stack not in contact with a DVONN piece is removed from the board.
A stack is in contact if it has a DVONN stone, or is adjacent to another stack in contact.
A DVONN stone is always in contact with itself.
GOAL - The game ends when both players cannot move. Wins the player with more stones in the stacks he controls.
If both players have an equal number of stones, the game is a tie.

Since a stack cannot move while it has no freedom, in the start of phase 3 only stacks on the edge can start moving.

Some examples

In this position, the stack at cell d4 cannot move because it is surrounded.

The white stack with the DVONN piece at f7 can move to d5, removing f8 which will be out of contact. 

After that, the black single stack at g6 moves up to the DVONN at h7, he will remove the 3 stones that make the g5 stack.

Some words from the author: 

When placing the pieces on the board, make sure that you put enough of them at the edge and close to the DVONN pieces. In the beginning of a game it is important to have pieces at the edge because you may not play with the pieces that are surrounded at all 6 sides. Having pieces close to the DVONN-pieces can be important to control them in a later stage of the game. 
Don't put too many of your pieces close together. However, having a cluster of pieces in the centre of the board may give you the opportunity to separate the piece on one side of the board from the pieces on the other side. Sometimes that can be very powerful - but only sometimes! 
When making a move, you neutralize an opponent's piece each time you play on top of one. A neutralized piece is like a piece that is captured (it remains in play, indeed, nonetheless it is one piece less for your opponent to play with).
Try to keep as many of your pieces mobile. Keep in mind that the higher a stack gets, the more difficult it becomes to move.
Be careful when your opponent is in control of a DVONN piece. Check where he can go to with the DVONN piece and how many of your pieces will have to be removed if he moves it. If it is too dangerous, then try to immobilize the stack by making it higher.
The last moves are very important. Often the player with the most mobile pieces at the ending stage of the game will eventually win. In other words: try to make your opponent pass his turn before you must do so yourself.

More information can be found at the GIPF project website - DVONN it's the 4th game of a series of 6. You can play DVONN at www.brettspielwelt.de. There is a ZRF to play Dvonn with Zillions.