In short, focal points are the squares used to obtain a fantasy position.

The h6 and f8 squares are examples of future mating focal points.  The key to understanding where focal points are on the board is to understand what happens at a focal point.  When the Bishop moves to h6, it turns and attacks the f8 square.  When the Queen moves to f8, it turns and attacks the king for checkmate.  So it is this turning ability that the square offers to a piece that makes it an important square.

Focal paths are the strategic roads that Pawn's or pieces take to get to the fantasy focal points.

As in motorcycling, you must look into the turn so that you see if obstacles are in the road ahead of you.  It is vital that the opponent's Pawn's or pieces are cleared from the important strategic paths.

In diagram #2, the connecting path f8 - h6, between the pieces, is what brings harmony to the Queen and Bishop.  In this case, it is very important that pawns and pieces be cleared from the (f8-h6) diagonal and the 8th rank.  So two things are going on here.  The pieces are being brought together by connecting to each other's paths and also the attack is being brought together by clearing the 8th rank of enemy pieces that might be able to stop the attack.

8 7 6 5 4 3 2 1
	a      b      c      d      e       f       g      h

This clearing of the paths and bringing together of the pieces is called "Harmony".

Harmony is the mark of the great player.

Kasparov, Garry vs Jussupow, Artur
E15 URS-ch49 Frunze 12. 1981

White sees that the Black King has barriers all around it.  These barriers are set up by his own pieces and the White Rook.  If White could just find another focal point to attack the King.  A Queen on the focal point f5 would turn and attack the King for mate.  A Knight on the focal point f6 would lead to a favorable exchange.  However, one of the squares in the Knight's focal path, e4, is controlled by the opponent's Pawn on f5.  The same Pawn on f5 also blocks the Queen's focal path.  This means that the Pawn on f5 is overloaded with its blocading duties.  Whenever you see an overload, the decoy maneuver should jump to the top of your list of things to look at.

1.Ne4! fxe4

Clearing the Queen's focal path.

2.f5 Rg5?

8 7 6 5 4 3 2 1
	a      b      c      d      e       f       g      h

Black should have brought the Queen over to its turning square f8, which is the Black Queen's defensive focal point, to contest the White Queen's focal point and path.

3.Rxg5 hxg5 4.f6 Kh6 5.fxe7 Qxe7 6.Bf7! d6 7.Rf1 g4

8.Bxe6! Qxe6

Winning the Queen's turning square on h4!

9.Qh4+ Kg7

Black Resigned because of Rf6, connecting to the Queen's path at h6 with overwhelming harmony!