10.  QxKt         QxQ
11.  PxQ          B-Kt5 double ch
12.  K-Q1         R-K8 mate

A further example in which the loss of moves occurs, though not so glaringly, is the following famous game, which Morphy played against the Duke Karl of Brunswick and Count Isouard in the Royal box at the Paris opera-house.

1.  P-K4          P-K4
2.  Kt-KB3        P-Q3

According to the principles set out above, Kt-QB3 would have been better, since the text move shuts out the King’s Bishop.

3.  P-Q4

Now the King’s Pawn is attacked twice.  It would be bad to support it with Kt-QB3, as White would exchange pawns and then Queens.  Black would thus forfeit his chance of castling and lose much time in bringing the King into safety and the Rooks into play.  P-KB3, of course, is impossible, as it is not a developing move, and moreover blocks the natural development of the King’s Knight.  Protecting the pawn with the Queen would also block other pieces, and QKt-Q2 cannot be good, as it blocks the Queen’s Bishop.

Since it seems impossible to protect the King’s Pawn, the only alternative would be to exchange it; indeed it is on the whole the best course, although it allows a White piece to take up a dominating position in the centre.  Wishing to avoid this, Black plays

          3. ...  B-Kt5

and, by pinning the opponent’s Knight, indirectly protects the King’s Pawn.  This manoeuvre is, however, ill-advised, as Black is forced to exchange the Bishop for the Knight.  The Bishop will have moved twice, the Knight only once, therefore White will have gained a move for his development.

4.  PxP BxKt

Should Black play PxP at once, White would exchange Queens, release the pin, and win the pawn.

5.  QxB PxP
6.  B-QB4

White has now two pieces more in play than Black, instead of only one, and the mobility of the White Queen, which Black himself has brought out, begins to have a threatening effect on Black’s game.

6. ...             Kt-KB3
7.  Q-QKt3         Q-K2

Black cannot cover his King’s Bishop’s Pawn with Q-Q2 because 8.  QxP wins the Rook, whilst now Black could play 8. ...  Q-Kt5ch in reply, forcing the exchange of Queens.  The text move, which is forced, blocks the Bishop, and at the same time prevents the development of the King’s Rook, all of which is the direct consequence of the loss of one move.

8.  Kt-B3

White rightly disdains the gain of the Knight’s Pawn, but prevents the exchange of Queens in developing a piece.  He proves the superiority of his position much more convincingly in that way.  Black must now lose yet another move to protect his Knight’s Pawn.

8. ...             P-B3
9.  B-KKt5         P-Kt4

Black must try to develop his Queen’s Knight at last.  He cannot play QKt-Q2 at once, since his Knight’s Pawn would again be unprotected; therefore he plays the move in the text, probably thinking that now White also must lose a move to withdraw his Bishop.  But in view of the fact that Black’s game is wholly undeveloped, and that he plays practically several pieces down, White sacrifices his Knight for two pawns:  he foresees the position which occurs a few moves later, when Black is hemmed in on all sides.