Greek gift sacrifice + test yourself!
Conditions for the attacking side: Bishop is sacrificed on h7, the knight must be in the range of g5 square, the queen must be in reach of h5 square or diagonal b1-h7.
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 prevets black king from escaping to the center.
The defending side usually has 4 options after the classic 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: when the withdrawal Kg8 is not good, the defending side usually reaches for Kg6.
- withdrawal of the king to h6: the attacking side usually 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: the attacking side does not bring new pieces to attack with a tempo (f.e. Ng5+ or Qh5+) and the defending side uses this tempo for a counter attack, exchange of the attacking pieces, etc..