public void insertvariation ()
	// insert an empty variation to the current
	{
		if (Pos.parentPos() == null) return;
		getinformation();
		int c = P.color();
		back();
		Node n = new Node(2);
		Pos.addchild(new TreeNode(n));
		n.main(Pos);
		Pos = Pos.lastChild();
		setlast();
		P.color( -c);
		showinformation();
		copy();
	}