Greek gift

Pattern # 38 This technique is explained in ebook Fundamental Chess Patterns

Standard Bishop sacrifice on h7
Gioachino Greco, also known as Il Calabrese, 1600 - 1634. After his early death, a game collection was published containing 150 games with his own annotations.

Additional different patterns can be found on this page of mine: Patterns

This classic bishop sacrifice (also known as the Greek gift) is the oldest and most studied of the sacrifices .

The conditions that are necessary for a successful attack:
black Knight not on f6
a white pawn on e5
no Bishop on e7
a white Bishop on b1-h7 diagonal
the other Bishop on c1-h6 diagonal
Knight can reach g5
Queen can reach h5 or h3

For the defending side there are also known conditions:
the knight must be in reach of square f6 or queen/bishop must be on the b1-h7 diagonal.
The worst square for the rook is usually f8 since it prevents black king from escaping to the center.
The defending side usually has 4 options (seldom successful) after the bishop sacrifice :
- withdrawal of the king to g8: defending side usually can defend h7 square with the knight (from f6 or f8) or puts bishop/queen on the diagonal b1 - h7.
- withdrawal of the king to g6 (better if a mate sequence is detected with Kg8). Tough times anyway.
- withdrawal of the king to h6: if the attacking does not have a dark square bishop (on c1-h6 diagonal) and it has a pawn on h4, which prevents Qg4, Qh4 maneouvres.
- declining the sacrifice (wise if a mate sequence is detected!): the attacking side does not bring new pieces to attack with a tempo (Ng5+ or Qh5+) and the defending side uses this tempo for a counter attack, exchange of the attacking pieces, etc