2023/12/01: "Deflection/Attraction/Fork!"

White obviously wants to promote and prevent Black from promoting.  Also, if there is a mass exchange, Black's g pawn might become a threat.

1. Ke5, to grab the opposition, ordinarily a good thing, probably is bad since it allows 1. ... Nf3+, gaining a tempo and freeing the h pawn to start moving.

1. Nf5+ Kf6  2. e7 [White will gladly give up the Knight in order to promote] Kf7  3. Kd6 [must defend the pawn before moving the Knight] Ng4 [better than 3. ... Nf3 as it defends f6, which I later found out was crucial]  4. Nh6+ Ke8  5. Ng8 [5. Nf5 just allows Black to return to f7] h2.

Wait:  4. Nh6+ is not possible if the Black Knight is on g4.  Can White somehow get his Knight to h6 before Black gets his to g4?  Is that even the correct idea?

1. Nf5+ Kf6  2. Nh6, which prevents 2. ... Ng4.  Black could just return to e7 but that allows 3. Ng8+ Ke8  4. Kd6 Ng4 and again, White cannot play Nf6.

Could this involve Zugzwang?  If the pawn structure on the Qside was locked and the Black King did not want to move because he'd lose a good defensive position, he would have to push ... g4, which would prevent the Knight from using that square.  Once Black moves ... Nf3, there is no way to prevent White from playing Nf6 without taking too many moves.  .  Then maybe White could make headway.

1. Nf5+ Kf6  2. Nh6 Ke7  3. a4.  Black does not want to move from e7 but if he plays 3. ... g4 the Knight is still stuck in the corner so he will play 3. ... Nf3.  White wins with 4. Ng8+ Ke8  5. Kd6 followed by 6. Nf6 and 7. e8(=Q).

No, that was wrong.  And even after getting the first two moves right, I floundered for the 3rd move. 

I thought I had to play 3. Kd7 to protect e8 but that allows Black Ne5+ and if Kd8 then Nc6+.  That's why I thought I had to prevent ... Ng4.  I didn't see the Knight deflection until after I had committed to my plan.  The deflection works because now it will take the Black Knight 2 moves to get to e5 to attack the King on d7 but he doesn't have 2 moves to spare.

After running it through the engine, I see now my mistake:  I had Black trying to stop White's pawn.  Instead, Black promotes his own.

I guess I out-thought myself.

In hindsight, I've used this very tactic myself in at least 2 games, where I fork the King and Knight to get the Knight to abandon the promotion square.  This puzzle was more complicated as White then had to move the King to protect the promotion square but the idea was the same.

Notice there is no Royal Fork at the end because promotion comes with check.