public boolean isAdjacentToAnyPiece(PieceCoordinate coordinate) {
		Iterator<Entry<PieceCoordinate, HantoPiece>> pieces = board.entrySet().iterator();
		PieceCoordinate next;
		while(pieces.hasNext()) {
			Entry<PieceCoordinate, HantoPiece> entry = pieces.next();
			next = entry.getKey();			
			if (next.isAdjacentTo(coordinate)) {
				return true;			 
			}
		}
		return false;
	}