Reverting to the opening moves of the Giuoco Piano, in answer to 3. B to B 4, Black may play (instead of 3. ... B to B 4), 3. ... Kt to B 3. This constitutes the Two Knights' Defence. White may continue with 4. P to Q 3, or Kt to B 3, or adopt a more spirited line of play with 4. Kt to Kt 5. Black's defences being 4. ... P to Q 4. or 4. ... Kt takes P. We append one or two leading variations:
| WHITE. | BLACK. | ||
| 1. | P to K 4 | 1. | P to K 4 |
| 2. | Kt to K B 3 | 2. | Kt to Q B 3 |
| 3. | B to B 4 | 3. | Kt to B 3 |
| 4. | Kt to Kt 5 | ... |
In the Giuoco Piano, where Black's Knight would be still at Kt sq., this advance would be bad, because Black could reply 4. ... Kt to R 3,
defending the K B P. Here, however, it is the best move. Black's best defence is
| ... | 4. | P to Q 4 | |
| 5. | P takes P | 5. | Kt. takes P (?) |
Not to be recommended. The best move is 5. ... Kt to Q R 4.
| 6. | Kt takes B P (!) | 6. | K takes Kt |
| 7. | Q to B 3: ch. | 7. | K to K 3 |
In order to defend the Knight, which is twice attacked. 7. ... Q to B 3 would be bad policy, for in such case White would play 8. B takes Kt: ch., B to K 3; 9. B takes Kt, P takes B; 10. Q takes P, with three Pawns ahead.
| 8. | Kt to B 3 | 8. | Kt to K 2 |