Copyright (c) 2002 Walter Joris
This game is played on a 6x6 board:
- TURN - On each turn, each player drops a friendly stone on an empty cell.
- In the following cases, stones are transformed into neutral stones:
- Custodian - an enemy stones becomes neutral when placed between two friendly stones (in an orthogonal or diagonal line).
- Intrusion - two enemy stones becomes neutral when a friendly stone is dropped between them (in an orthogonal or diagonal line).
- GOAL - When the board is full, wins the player with more friendly stones.
Intrusion and custodian transformations
If White plays at  he will transform by intrusion the four marked black stones.
If Black plays at  he will transform by custodian the marked white stone.
This game can be player with just pencil and paper. It is presented at 100 Strategic Games for Pen and Paper by Walter Joris.