Weekly Puzzles 3

This is my third post in this series. In this week's post I also added a simple, yet beautiful endgame study at the end. I hope you will enjoy the puzzles!

Solutions

This position does look quite dangerous for black, but no clear way to break through is apparent. But the f6-square isn't too well protectet.
1.Nxd4 Bxd4 (1...Nxd4 2.Bxe7) 2.Qxd4!!
Removing the defender of f6.
2...Nxd4 3.Nf6+ Kf8 4.Bh6#

1.Nf6+ Bxf6 2.Qg6+ Bg7 3.Qxf7+ Kh7 4.Rd7!
This is an important move, white threatens mate on g7.
4...Ne8 5.Be6!
And black will lose their queen.

White wants to bring their queen to h5 and mate black's king, but the black knight on f6 protects this square.
1.Bxf6! g6 2.Qh5!! gxh5 3.Bh7#

1...Qa5!
Black uses the fact that the a1-rook has to stay on the first rank and black wins material.
2.Rad1 (2.Rxa5 Rf1+ 3.Qg1 Rfxg1#) 2...Qxd2! 3.Qxd2
Again, the rook has to stay on the first rank.
3...Nf2+ 4.Qxf2 Rxf2

1...Nd4!
Black attacks the white queen and prepares a fork on f3. Note that 1...Ng5 with the same idea doesn't work because of 2.Rd8+ Rxd8 3.Qxd8 Kh7 and white has time to move their bishop.
2.Qxe5 Nxf3+ 3.Kf1 Nxe5

The problem for white is that black might be able to give up their bishop for one of the pawns and force a draw or maybe even a win. So white needs to chase the bishop away from the b8-h2 diagonal, but the bishop has too many squares currently.
1.d6!
Taking the d6-square away from the bishop. 1.Ke8? Bc7 2.Kd7? Bd6 shows why this square is so important. Black's bishop will stay there and take on c7 as soon as white pushes their c-pawn.
1...exd6 2.Ke8 Bc7 3.Kd7 Bb8 4.Kc8
And the bishop has to go to a7 and white will be able to promote their pawn.