Can White Stop The Pawn??

[@JustAnotherCommenter]

Black: *is about to win White: _in Nelson's voice_ White to play and DRAW! Black: Oh crap.... White: _in Nelson's voice_ Well if you had a chance to lo- Black: Stop, I give up.

[@plokenv]

Underrated comment 🏆

[@garysuderman174]

I have a chess puzzle, how do I send it to you?

[@tykemorris]

Black: "why am I always black on Nelson's puzzles?"

[@fajdek7032]

​@@tykemorrisIncase this is an actual question, it's because white starts the game therefore it makes sense that every puzzle starts with white to play, it's also for the sake of consistency.

[@lowylumunon5008]

4.36 bg4​@@fajdek7032

[@redpacific359]

Pawn: im going to be a queen Knights: nope sorry sir

[@Crowsinger]

Enemies of transsexuality. 😎

[@yyyy-uv3po]

You can't blame Black for rage quitting this game!

[@wernerviehhauser94]

making the opponent to rage quit is a win.

[@plokenv]

​@@wernerviehhauser94yeah lol

[@danielschechter8130]

It's a game. Rage is bad sportsmanship.

[@mittarimato8994]

@@danielschechter8130 Rage is good sportsmanship. It shows you care about the game. If you can control your feelings, it means you do not love the game. If you rage at your opponent, then that's a different story. You have to rage against yourself.

[@edersonnico]

Rage quitting is a defeat while the other option is a draw.

[@3characterhandlerequired]

I didn't "solve" the puzzle, but I did see the "only move to not lose" -options. So I could play the puzzle and get the right result. I would have taken me a bit to realize that there is a continuous loop to play which prevents black from promoting the pawn ever.

[@christopherheckman7957]

This reminds me of some episodes of the TV show Columbo. Peter Falk would ask the killer some questions, get ready to leave, and then say, "Oh, one more thing ..."

[@christopherwellman2364]

Some episodes? Every episode!

[@wreckim]

Love Columbo. Murder by the Book etc...classics.

[@Watermelon_Man92]

I saw the first two knight moves but then I got confused. It seemed like the bishop should dominate the knight but I guess there are so many stalemates on the board that it doesn't matter. Fascinating puzzle.

[@tsundude4320]

Couldn't the bishop just own both knights? If whites king owns the bishop then the king just checkmates

[@Watermelon_Man92]

​@@tsundude4320: The problem with Black's game is that his king is tied to the pawn. Without this pawn, Black can't win. Even if Black doesn't take the knight after 1.Ne5+!!, he runs out of real estate. For example 1...Ke3 2. Ng4+ forking king and pawn draws the game. Or 1...Ke4 2.Kg2! (Black can't win if White's king is on f1 unless both knights are captured.) There are many things Black can try but they all end in similar disappointment.

[@toriless]

Sac the move the king, I think but I pause 17 seconds in and am only 1600

[@toriless]

Then not the where is the edit button

[@Broockle]

Stalemate mechanic in chess always felt weird to me.

[@anonymousanonymous9271]

Bruh

[@Gratios]

@@anonymousanonymous9271the theory that keeps popping up is the siege analogy where the enemy has nowhere to run and is thus surrounded. Of course this is a boardgame and so the method of attrition/starving out is a gruesome and out of place analogy for a clean game, but it still feels whacky.

[@BlackHalo87]

I don't play chess, but if your king is trapped like that, shouldn't that lose you the game? I agree it feels weird

[@alphax4785]

The stalemate is the kill screen of the game, the stalemated player cannot make an illegal move and the attacking player can't checkmate outside of their turn, thus the game 'hangs.'

[@Broockle]

@@alphax4785 What's a "kill screen"? You could easily change the rules so the king has to make a move into his own demise. That's not the issue at all. They keep it around cause someone centuries ago must have thought it makes the game more interesting and now it's stuck.

[@michaelrnahas4425]

What if the black moved the bishop backwards to e5 instead of capturing? Time index 4:37... actually I think I see it white just moves the knight back in front of the pawn again and it's rinse and repeat

[@tykemorris]

Yes. The Bishop is in the perfect spot to trap the knight but if it moves anywhere the knight has a safe move. With the white king on g2, the Black King can't capture our knight without losing the pawn.

[@fairyfellermasterstroke]

1:25 I calculated up to this point, but then I was like, damn, I can't see my king moving anywhere where it would be a stalemate. Without realising he can't move at all.

[@jovindsouza3407]

Before playing the video, I'm going to guess the first move is Ne5+. If black plays Ke2, white takes the bishop and wherever black moves white will be able to stop the pawn - ...Kf1 Ng4, Ke1 Nfd3+, Kd1 Ng4 e1Q Ne3+. If black plays Bxe5, then white will play Ng3, where black cannot take the second knight due to stalemate and has no way to make progress since the knight covers both e2 and f1. If black makes a waiting move (eg. ...Bf4), white plays Nf1 Ke2 Kg2, drawing as black again cannot progress. Edit - yay I was right!

[@Fatih-jq2it]

East or west Papa Nelson’s puzzles are the best

[@crowreligion]

1:59 But what if black gets a rook instead and we have to play Kh3? Can we still draw?

[@Dash123456789Brawl]

In that case you need to get a Keyblade.

[@crowreligion]

@@Dash123456789Brawl What does that mean?

[@Dash123456789Brawl]

@@crowreligion Well I don’t have the full context, because I’ve never played any of the games, but when I see KH3 my mind goes to Kingdom Hearts 3, which was rumoured I think for over a decade before it was finally announced.

[@Pika250]

What about if on 5:06 black plays bishop anywhere along b8-h2 diagonal *_EXCEPT_* taking the knight on g3? Not Kh2 Bxg3+ with f1=Q# to follow. Nf1 therefore and we're back to square one.

[@Gott-yx1id]

Just Go Back to f1

[@abdush3268]

2:02 black can also promote to a knight and proceed to capture white knight in next move, and mate with bishop + knight, right?

[@jovindsouza3407]

Irrelevant, as black can win faster by taking the knight.

[@Fatih-jq2it]

If he captures the knight it is stalemate

[@aandykf]

@@Fatih-jq2it No, when the white knight gets captured by the new knight, G1 and H3 would be available for the white king.

[@BigDBrian]

they could, but it's easier & faster to just take the knight and get a queen.

[@Zwischy]

I think for B-N-K to mate a lone K, you have to drive the solo king into the corner as the same color as the bishop. In this case, I don't THINK black can drive white out of the corner, but I could be wrong.

[@joe_ninety_one5076]

What happens if the initial knight sacrifice is declined?

[@lordd007]

Well the Black King would have to move and then I think white knights may have the advantage

[@rickdesper]

Either the king will be able to move to g2 or the other knight will be able to take the bishop. Either way, black won't be able to promote.

[@MrAM4D3U5]

Very difficult puzzle but very interesting. I don’t encounter stalemate puzzles too often , good video

[@altararitan5633]

From the position where black bishop is at e5, black king is at f3, black pawn is at f2, white knight is at g3 and white king is at h3, I think there is another move for black to try which is a bishop move on b8-h2 diagonal which is NOT f4 (or taking the knight). Then: -White cant move the king since bishop would just take the knight with check. -Only knight move that stops a promotion is Nf1 (other knight moves dont lead to a stalemate trap either) -After Nf1 black plays Ke2 and now white cant move the knight anywhere. (any move with the knight would lead to its capture by bishop or king) -So after Ke2 white plays Kg2. -After Kg2 there are 2 paths for black. First is Bishop staying on the b8-h2 dioganal (b8-c7-d6-e5). If this is the case there is Nd2 by white and black king cant take the knight since white would take the pawn(Kh1 works aswell here). Black cant make progress here since while will keep moving the knight Nd2-Nf1 if black doesnt move the bishop from the b8-h2 diagonal. - 2nd path if black bishop goes to a7-g1 diagonal (a7-b6-c5-d4) after Kg2. This time white knight will hop between Ng3-Nf1 and again black cant progress so its a draw.

[@S8EdgyVA]

Well, I had a correct guess but I didn't realize that it'd be a stalemate

[@Inuus]

1:01 Instead of taking a knight, black king should move to e-2.

[@rickdesper]

Ke2 would be followed by Nxf4+. Then black has no bishop. If he drops to e1, Nd3 would fork the king and pawn. King moves, Nxf2. If he goes to f1, Nf3 is a stalemate. If he moves away from the pawn, Kg2 moves into position to take the pawn or queen. Without the bishop, there's no hope to promote the pawn.

[@RichKonfusion]

From the final postion what happens if Black promotes Pawn White knight takes black queen Black king moves down 1 White knight is forced to move to a position to be taken by Black Bishop but crucially not in a position to force white stalemate? So then you have a bishop and a king to get a king in CM? What am I missing there?

[@mariomario-dy1kc]

A bishop isn't enough to get a checkmate.

[@Kranford]

That is some grade-A magnificent bastardry

[@kennethprola5136]

Why wouldn’t black just move the bishop off of the diagonal that puts the king into a potential stalemate scenario?

[@warmike]

Then white would be able to shuffle the knight between f1 and h2.

[@DeuceGenius]

Wow thats a hell of a good puzzle. Hope to use this in game

[@smallmetalowl3209]

A neat try at the end is Nh2+, which fails because of Bxh2 Kxh2 f1=R! (not Q because stalemate) Kh3 Rh1#

[@triharders2456]

I wa thinking abt that

[@stuartwakefield1657]

There's a lot of players who think a stalemate should be a loss. The King is trapped and can't move and should surrender which is a lost game.

[@tsundude4320]

1:29 hows it a draw?

[@Karanthaneos]

You can't move your king into check. If you have no valid movements but your king is not in check it's a stalemate and the game ends in draw

[@tom-kz9pb]

"White to move and draw" is a more accurate title than "Can white stop the pawn?" . You actually cannot "stop" the pawn, but just force stalemate if it queens. Saw the first two moves, right away, but missed that a couple more moves of analysis were needed to really make it complete.

[@JungleLibrary]

Well if you checkmate before a pawn can promote, that's stopping the pawn (from promoting) in my book. I don't like clickbait either, but it seems fair in this case. It can be rephrased as "can you stop this imminent threat?"

[@lowylumunon5008]

​@Jungle4.36 bg5Library

[@yusukekamui591]

Can a Knight and Bishop deliver checkmate? If so, on time 2:06, promote the pawn to Knight.

[@Zwischy]

That's very clever; however, I believe it cannot be achieved here because you must drive the opposing king to the corner that matches the bishop's color. In this particular case, Black has the wrong colored bishop! Perhaps it IS possible to drive the white king out of that corner, into the opposite corner, and deliver checkmate? However, my brain broke when I tried to analyze your idea so I'm unsure.

[@Zwischy]

Don't forget, also, the 50 moves rule: There are no pawns to move here, so Black would have to deliver checkmate in 50 moves. If checkmate here is possible and done right, I THINK it should only take about 20-odd moves but I'm no endgame expert.

[@christopherheckman7957]

Or a rook. Then 1. Kh3 Rf2 2. Nf1 (best) Rxf1 3. Kh4 Rh1 is mate.

[@wallacehoward2792]

@@Zwischy After ...f1=N+ it's mate in 22. Also, Black had two other ways to mate: ...f1=R is mate in 3 (as mentioned by christopherheckman) and simply ...Bxg3+ is mate next move.

[@MikkoRantalainen]

@@Zwischy Bishop and a knight can always mate a lone king but it takes 32 moves in worst case if I remember correctly (king in wrong color corner, both bishop and knight close to center of the board). However, there's the 50 move rule which basically tells that if the attacker makes even one non-optimal move, the defender can probably live for 50 moves in total and draw that way. For a perfect play, bishop and knight wins every time.

[@musclesmouse]

Nice. I normally do not think about going to stalemate

[@dijax7863]

to mate white you need to drag the game out. you have 50 moves to swing the black king around the top forcing the knight and white king to block the pawn, once they are on the wrong side, you can pinch them out.

[@dzerkle]

That’s a pretty hard puzzle, especially if,you don’t think of forcing a stalemate.

[@giovannigino3675]

Black is not forced to take the knight with the bishop

[@rickdesper]

The alternative isn't better.

[@mrosskne]

in the first move, couldn't black just move the king instead of capturing?

[@kornel3564]

This is exactly what I miss in the video

[@warmike]

There's also an interesting variation where black don't take the knight on the first move and instead play Ke2.

[@lordd007]

White K takes Bishop at f4 causing check at e2. Black K goes to e1 and K will fork it. Of Black K goes d1, it's safe but white K will approach the pawn. Same if Black K goes to d2. So Black goes to e3 and the K will continue checking

[@hrayrbarseghyan5453]

Found from beginning, except considering Kd1. Thank you very much

[@jaakezzz_G]

What if he doesnt capture the first knight

[@sterlingmullett6942]

The black king is in check so the knight must be captured, or move the king. If black moves the king than white will have two free roaming knights available to take the pawn using the methods/moves shown in the puzzle. Two knights can jump around a lot and clean up pieces if played properly. With the limited spaces available to protect the pawn it would be bad to leave that knight around after the check. $0.02

[@landsgevaer]

So, in that final position the pawn can move and promote. The queen might be captured by the knight, sure, but given the title of the video: no, the pawn cannot be stopped. 😋

[@NicknineTheEagle]

If the pawn/queen is captured, I believe it's a draw since neither side can physically achieve checkmate with the remaining pieces so Black still fails. They can try to dance around trying to squeeze that pawn through but as long as white doesn't make a fatal error, this will inevitably end in a draw due to the same position repeating 3 times.

[@jeff13379001]

I got every move it this puzzle correct, but I want to point out a blunder from black. From 2:00, f1=B or f1=R wins the game for black.

[@TKZprod]

Nice catch, at 2:00 you even have Bxg3 and then f1=Q#

[@samtoubodjona332]

Why didn't you analyse the black king moves instead of taking on e5? Draw doesn't look so obvious if king e2 for example.

[@oenrn]

Ne5+ Ke2, Nxf4+ Ke1(or Kf1), Nd3+ and that pawn is lost.

[@MegaBurcho]

Thanks for sharing this interesting puzzle.

[@Dangeff]

That’s a little wonky tbh, I guess it’s just the rules of the game, but why would the bishop at g3 cause a stalemate? Sure, white is not in check but they also can’t make any moves… Technically black does have moves to make, it’s just not their turn. But white is completely stuck, so how is it a stalemate… can someone please explain?

[@minatic1148]

a stalemate is, when the player who has to move, is unable to, while not being in check, a stalemate in chess is always a draw.

[@Dangeff]

@@minatic1148 ahhh gotcha, so if one is losing, instead of going for an improbably win, they can try and get themselves ‘stuck’, per say, to get the stalemate

[@toriless]

At 17 seconds, the first 2 moves are obvious but there is more

[@JetGatlingChess]

Only one question: what if white not takes after first knignt move? Very hard to calculate.

[@JetGatlingChess]

Looks like endgame queen vs. knights. Don't know how its finished. Probably a draw.

[@Volkaer]

Why would the black simply not move the bishop off that diagonal at the end though? To like C1 or H6? Or even better, maneuver to where they can defend the pawn without the knight threatening the bishop in return, so you avoid the situation where white can push black's king away from the pawn itself, allowing the white king to take it?

[@Ravispartansolutions]

At 2:00 minutes you can have an elephant instead of queen and you can avoid stalemate and win

[@user-xy5yg6se1k]

i figured the very first move and i feel incredibly proud

[@danfg7215]

I like how I got everything wrong, even though I thought really hard. That means I'm stupid.

[@edwardnedharvey8019]

I'm not sure black is out of moves at that point. I would move the bishop somewhere far away, covering the pawn, allowing the white king to move up.

[@tykemorris]

I got this one but it was good. If I do enough of these puzzles I'll get over my fear of sacrifices.

[@KororaPenguin]

Is it really a zugzwang if there's a way out of it?

[@frakplease3771]

These puzzles are tough

[@Boudicca-the-musical]

At 4.15 what if black plays Be3?

[@oenrn]

Ng3+ and either the white king keeps moving g2-h1-g2 with the knight controlling the promotion square, or if the bishop retakes the diagonal then white moves the knight back to f1 and there's the stalemate threat again.

[@frfancha]

I don't see why black can't move the bishop to avoid the stalemate?

[@Zwischy]

Because then white can either shuffle the king between h1 and g2, or the knight between f1 and g3.

[@frfancha]

​@@ZwischyThank you.

[@saofanidwi]

It's quite brutal since Black is winning but is forced to chose how they would draw. Either take the stalemate or repeat move

[@BillGraper]

4:48 Bd2 ???

[@Usernhhh77776]

Ne5+ if Bxe5, Ng3+ Bxg3 is stalemate.

[@greatbriton8425]

19th century people were really smart

[@siddhantkapil8367]

I won't end up in this position if I knew how to defend this position.

[@ytmancovian6415]

As a 700 Elo player I was able to complete the puzzle (big part of it was at the beginning)

[@danielschechter8130]

These things always look impossible to me. Very cool.

[@aaronwalderslade]

Surely if we can get the black bishop to e1 promotion of the pawn is inevitable

[@Lovuschka]

Hey, we have detected anti-monarchistic content. To be exact: Stopping queening. By Royal Decree, to absolve, you must continue the Chess Adventures series now. Thanks for the cooperation!

[@kujklokp]

Why does Nh2 lose instead of Ng3 in the end? It's the same principle.

[@noatrope]

After Nh2 Black moves Bh2, at which point White is not in stalemate because the bishop is unprotected. Kh2 is forced, leaving the pawn free to promote.

[@NJDJ1986]

I guess white gets stalemate at the end since knight will be captured in g3 while the king is stuck in h1!

[@eirikraude854]

Awesome! Keep those puzzles coming! :)

[@RamKumar-gy9nb]

excellent... thank you very much

[@FustinJields]

saw every move for once cool traps

[@eugenebirukov5117]

A case when extra knight is a burden to get rid of.

[@dmitripogosian5084]

So what if black does not take the first knight ? That would instructive to see

[@slapmyfunkybass]

This is the best Chess channel on here. Most others are them playing, this is much better.

[@terratorment2940]

Yeah he just got to flip the table over

[@thomasp.5057]

I did NOT solve it on my own but I had a lot of fun!

[@Pining_for_the_fjords]

As somebody who doesn't play much chess, the fact that a stalemate is a draw and not a win for the attacking player seems like a silly and arbitrary rule.

[@apersunthathasaridiculousl1890]

I’m so proud of myself for seeing those first moves 😂

[@sami9095]

Plot twist: black resigns

[@asdfgoogle]

What about Nh2 at the end?

[@frankpulmanns6685]

Ok, but what happens if black doesn't take the first knight and just moves the king to e2? Doesn't that avoid the stalemate trap?

[@saulofontoura]

The other knight takes bishop with check. If black king moves up, then you stop the pawn with your king. If black king moves down to e1 protecting the pawn, you just deliver check with knight to f3 to push him away from the defense of the pawn.

[@EvertonSuarez-kg1lq]

1...Ke2 2.Nf4+ The idea is now take de pawn with the king and if 2...Kf1 to protect the pawn, then 3.Nd3+ and takes the pawn next move. 1...Ke3 2.Ng4+ and 3.Nxf2 1...Ke4 2.Kg2, if 2...Be3, 3.Ng4 and takes the pawn.

[@EvertonSuarez-kg1lq]

1...Ke2 2.Nxf4+ The idea is now take the pawn with the king and if 2...Kf1 to protect the pawn, then 3.Nd3+ and takes the pawn next move. 1...Ke3 2.Ng4+ and 3.Nxf2 1...Ke4 2.Kg2, if 2...Be3, 3.Ng4 and takes the pawn.

[@EvertonSuarez-kg1lq]

1...Ke2 2.Nxf4+ The idea is now take the pawn with the king and if 2...Kf1 to protect the pawn, then 3.Nd3+ and takes the pawn next move. 1...Ke3 2.Ng4+ and 3.Nxf2 1...Ke4 2.Kg2, if 2...Be3, 3.Ng4 and takes the pawn.

[@EvertonSuarez-kg1lq]

1...Ke2 2.Nxf4+ The idea is now take the pawn with the king and if 2...Kf1 to protect the pawn, then 3.Nd3+ and takes the pawn next move. 1...Ke3 2.Ng4+ and 3.Nxf2 1...Ke4 2.Kg2, if 2...Be3, 3.Ng4 and takes the pawn.

[@damo9961]

1 queen beats 2 knights? I'd take my chances

[@SephirothsBIade]

Did rules change in the past ten years? I remember zero legal moves due to self check resulted in a win, not a draw. Logic behind it was to never corner a rat.

[@deltalima6703]

Your memory is wrong. It was always zero legal moves and not in check equals a draw.

[@SephirothsBIade]

@@deltalima6703 is there a different endgame situation where an obvious loss somehow results in a win. I have several memories of highschool chess tournaments that this happened. Guessing I have memery merged this other rule, or all parties involved in those tournaments had this rule wrong

[@samuelelliott8453]

What about King to h4?

[@markharding6582]

I'm smart enough to understand everything said but most especially that I suck at chess. Although that last part was prior knowledge.

[@ralisgroffen]

2:50 i thought g2

[@Dc-kk9bd]

What if they dont take ur knight? I suck at puzzles because im like "y would they ever do that"? That only works if they do something stupid. Thats not stopping them, thats them stopping themselves

[@mariomario-dy1kc]

2 knights isn't enough to win so white is solely going for a draw. a bishop also isn't enough to win so black needs that pawn. Therefore, white will keep the black kind in check until it can kamikaze one of the knights to take the pawn.

[@deltalima6703]

Two knights will not get you there. Guys at my level do not blunder badly enough. Nobody cares what 1500s do, thats not chess.

[@farouqbaiti4315]

I really solved all moves of this puzzle.

[@mydreamynights]

5:06 amazing video, thank you. Always learning something new from you

[@All-star_Giga_Gargantuar]

Just finished looking at the thumbnail and came here to post the answer. Ne5+ is obvious, with the intention of getting rid of the knight to get stalemated after following up with Ng3 Bxg3. If Black doesnt take the first knight, you just go Kg2 and the pawn is stopped. gg

[@luispalou217]

Very good one

[@slyveonnumeros]

What if this is a bullet game?

[@constantinvasiliev2065]

Thanks!

[@rogerkearns8094]

The title gave it away, a bit We might have tried looking for a promotion and stalemate.

[@TommyStephenThompson]

Knight goes to e5 then other one goes next to king

[@kasperjoonatan6014]

enjoyed.

[@lyingcat9022]

IM Eric Rosen would die from ecstasy if he got this position as White in a time scramble.

[@station3913]

Workin' on our knight moves

[@isaachaze1]

tryin to lose the awkward queenin moves

[@deltalima6703]

Why does black have to take first knight?

[@kaioneal6160]

Yes Take the bishop If black king takes, block blacks pawn with you king He he promotes pawn fork it either the knight he didn’t take

[@HenZoid93]

4:16 why can’t the king take the knight???

[@tartarelin]

Может, но куда ходить белому?

[@ManuFortis]

I think I found a different strat, but... it kind of depends on how black moves per the different moves I have thought of. Instead of trying to corner the pawn immediately or distract the king with a check; I think there is a way to possibly win by starting with moving the king up to H4. From there, now the pawn could promote to a queen, but it's not on a direct line of attack anymore for the king. So it promotes anyways, but now has to move to check the king. Now this is where the knights come into play, but... I'm not quite certain on which to use first. Could still check the king with the D7 knight. But could also delete the bishop with the H5 knight. There is also the possibility of pushing on the Queen at F1 still, but that risks the bishop taking that knight. So take the bishop. The queen now might move towards the king, but the king might try to take the knight. So we let ourselves get checked by moving the king to G5. This keeps the king from taking that knight, while setting up the queen to move to G1 or G2, instead of possibly H3. H3 gives more options to the queen, where as the G's keep it on a straight line still. In any case, the only open space that doesn't lose the queen via the knight on F4, is G1. So it goes to G1 and puts the king in check. So the king goes to F5 to keep the knight safe from the king, but the queen now goes to G4 which keeps it safe while putting pressure on the King so it has to move away and sacrifice the knight. 1 knight left, 1 queen, 2 kings. I'm going to stop here, because going through all of that, now I think maybe winning ain't possible. But I leave you with that end of my ponderings to try that little bit as a puzzle. See if you can make it work, from both the original puzzle's start, and the end point I left it at here. There should be enough of my rambling for you to get an idea of what I am trying for. But if not, essentially trying to lead the queen into a trap with the knights using the king as bait. Perhaps its still possible and I missed something. I think it is. But I am most certainly probably wrong. Maybe I took the bishop too soon?

[@phoneoperator]

In the last position, why wouldn’t black just promote the pawn to queen and checkmate white?

[@dzerkle]

Knight takes queen, so that’s not a checkmate. The resulting position is presumably considered a draw.

[@Newtofinland]

I think nh2 also works

[@noatrope]

Nh2 leads to Bh2, forcing White to move Kh2, leaving the pawn free to promote (to a rook)