Solution Saturday

Here’s the solution to yesterday’s Chess Puzzle Friday:

White to move and win:

Hopefully everyone saw:

1. Bh7+ Kxh7   2. dxf8=N+ Kh8   3. Nxd7 +-

Okay, great if you saw that. But what if Black doesn’t take the bishop?

1. Bh7+ Kh8 2. dxf8=Q+?? Kxh7 3. Rxd7  and now black is in stalemate. Oops! Okay, but could white still win if he doesn’t take the white queen right away?

Let’s try 1. Bh7+ Kh8 2.dxf8=Q+?? Kxh7 3.Qxh6+ Kxh6 4. Rxd7 Bxh5 and this is a theoretical draw (R vs N).

But what if, instead, we under-promote like we did in the first line?

So, if 1. Bh7+ Kh8    2. dxf8=R+ Kxh7  3.   Rxd7 Kg7 (it’s not stalemate this time!) R7xf7 mate.

Okay, but there was another move black could have made:

1. Bh7+ Kg7 2. dxf8=Q+ ?? Kxh7 (same position we had before with Kh8). Maybe you are seeing a pattern here? Yup, under-promotion.

Let’s try 1. Bh7+ Kg7 2. dxf8=B Kxh7 3. Rxd7 

A quick review. If after the bishop check on h7:

• black captures on h7, we capture on f8 and under-promote to a knight.
• black moves to h8, we capture and under-promote to a rook.
• black moves to g7, we capture on f8 and under-promote to a bishop.
• if white ever promotes to a queen, black is able to draw or is in stalemate.

Watch the video below of this puzzle and solution from the source: IM Greg Shahade’s YouTube channel (https://www.youtube.com/watch?v=eceGtE9iKD4)