1.
[{B:2kr4/K1pp4/8/8/8/8/7Q/3R4}
{V:This problem was composed by Max Euwe, who was World Champion from 1935 to 1937, and it provides a nice introduction to the 50 puzzles. White to play and mate in two. Try your solution on the board.;h2d6;Correct, White prevents the defense ...d6 in the most dramatic way possible, by offering a queen sacrifice. Although there is no threat, every Black move creates a weakness which allows mate. After 1...c6 (or c5) White can play 2 Qb8 mate, while if the rook moves then d7 is not guarded, so White can play 2 Qxd7 mate. Finally, if Black accepts the sacrifice by 1...cxd6, then 2 Rc1 is mate.;Incorrect.;It is worth looking to see if Black has a strong defense already arranged. If so, then White's first move must either prevent it or prepare a reply. Here Black has the possibility to play ...d6, making it hard to see how White is going to deliver mate. So White must try to prevent ...d6.}]
