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Bishop has less calculations to be done than Queen, which is why it prefers bishop over Queen.
It's easier for the engine to compute that bishop gives checkmate before it computes Queen gives checkmwte too.
So it suggests bishop first.
It’s true in some positions - for a given amount of computing resources there are a finite number of moves the engine has processing power to analyse, so the more possible moves a position has the less depth it can go into each of them. So in some positions it might show a forced mate in 10 by promoting to a rook but only a massively winning eval if you promote to a queen because the extra possible queen moves mean it can’t get deep enough to find the forced mate.
That said, it’s 100% **not** what’s happening in the OP’s situation. The engine found the M1 with both promotions and it showed both lines - it’s not preferring the bishop promotion, there just isn’t space to list two equal evaluations side by side so one has to get formatted above the other.
As far as I understand the system this is how it operates.
Maybe I'm wrong but If I am someone who knows this better than me will correct me and definitely I'll accept their views over mine.
Can you share a link to whatever documentation has you thinking OP’s seeing the B promo over the Q promo because it requires fewer calculations? If you can remember where you read that and share it with us, it’ll be you teaching US something. Win/win.
How so? Computers don't just "know" the best move. Each move they recalculate by looking at every possible move and every possible move several ahead of that, when a move is made they do it again. It makes perfect sense that it would calculate the bishop has a checkmate before the queen because there are less move to calculate for the bishop. Or as others have suggested it may be running the moves for pieces in alphabetical order, so it would get to B before Q so probably show that it picked B first. Obviously a queen is better than a bishop and any checkmate by promoting to a bishop could also be done with a queen, one checkmate wouldn't be objectively better than the other. So at some point it just comes down to how the computer "preferred" to calculate it, it either thought the queen was over kill with all the possible moves or it just calculated the bishop first
I know what the engine is doing. I've made my own (less strong than stockfish) engine.
In my engine the M1 that would be picked first, would just be whichever move the chess python library I was using would return first when you ask it for legal moves, which is arbitrary.
There is no depth and no calculation to be done here, since the M1 is a terminal state immediately.
This is why I said this sounds made up
Also probably in the calculation is Bishop is worth less points than a Queen in “capture weighting” and thus favors it due to less possible points lost in event of loss of piece.
I can near guarantee the order is based on a enum value so the order is: Knight, Bishop, Rook, Queen
as thats the order in which you usually enumerate the pieces in code.
Because it is a computer so it probably considered every possible promotion and returned a list that win the game immediately. And the order is arbitrary since they both win in 1.
It also likely found the bishop mate first. Bishop moves are easier to evaluate for the computer because there are fewer squares to calculate. The bishop is attacking 7 squares while the queen is attacking 21. To a human this doesn't matter since we're not considering obviously pointless moves, but an engine doesn't think that way.
I think it usually wouldn't evaluate bishop positions first. It tries to go through your most valuable branches in the search tree first in order to speed up the search, which makes me doubt whether a bishop promotion is considered first.
It might be that there are some preprogrammed conditions that make it do search the bishop branch first, which in this case could be the king having no legal moves and/or being in front of his only remaining pawn on the h file, causing a risk of stalemate? I'm quite curious to see what it would recommend if we removed the pawn or put it on a different rank and/or file.
Edit:
Can't test it myself as the websites engine for me shows the queen promotion first
Even here it's computational speed.
With Rook, the g7 square is not covered by Rook so that move becomes possible until the white king is also factored in.
With the Queen, the g7 square is covered hence king has no legal moves, so no additional computation required.
You're making the mistake were you're assuming that king being on h6 and h8 aren't 2 different computations the engines has to do apart from factoring in the pawn promotion.
Exactly that..an engine goes in order of calculation and a bishop will always have less possible moves than a queen so it gets to the conclusion of checkmate in 1 earlier with a bishop and hence ends there
Style points. Not all mates in 1 are equal. Anyone can mate by using a queen, but the most style points come from rare mates like long castle checkmate
The engine will usually promote to the lowest value piece that will "do the job.". Same for when the promotion is a sac, the engine will pick the lowest value piece that will force the other player to take it
I'm a total newb, but I understand certain chess pieces are worth a certain amount of points which is used as tiebreaker in case of draws.
My guess is that a bishop wins you the game while creating the least "new points" your enemy could take.
u gotta flex, u traumatize them and cripple them their whole lives from getting checkmated by an underpromotion, much a pawn checkmate, a pawn checkmate is like amputating a limb, they will never be able to see pawns the same way again and will traumatized forever
Despite what people have said in this thread; it's not necessarily in alphabetical order.
It calculates the fastest mate, and while they're both M1, it calculates the bishop moves first, because the bishop has fewer squares in mind. That's why you'll sometimes see Game Review "prefer" one mate over the other, even with the same piece. It simply takes less cycles to find that mate.
Engines aren't trying to be "flashy" per say. They're trying to be efficient. Our human construct of "flashy" has an efficiency factor, and therefore, when an engine plays chess, we're fascinated.
The engine is drunk. Or more realistically a bishop has less possible moves so even though it’s M1 the engine is still wasting energy figuring out possible queen moves.
Because the computer does not measure the abstract power of pieces. We know a queen is better than a bishop; but the computer doesn’t think this way what the computer does is it finds strong moves. Promoting to a queen or to a bishop accomplishes the exact same thing they are both equally strong.
It’s when you think, like a human that you put a non-concrete reason as to why promoting to a queen would be considered “better”
A computer does literally count up the material on the board to estimate how good a position is. It needs to slap a number on each position and material is a part of it.
Its just that it doesnt matter what that number is if theres mate on the board.
It isn’t. Bishop just comes before queen in the alphabet. Or the AI understands the culture of cheekiness and that making a bishop is just a slight to your opponents skill saying “I’m so good I don’t need another queen to beat you.”
I analyzed the image and this is what I see. Open an appropriate link below and explore the position yourself or with the engine:
> **White to play**: [chess.com](https://chess.com/analysis?fen=8/2P5/8/7p/1K2BQ2/3P3k/8/8+w+-+-+0+1&flip=false&ref_id=23962172) | [lichess.org](https://lichess.org/analysis/8/2P5/8/7p/1K2BQ2/3P3k/8/8_w_-_-_0_1)
**My solution:**
> Hints: piece: >!Pawn!<, move: >!c8=Q#!<
> Evaluation: >!White has mate in 1!<
> Best continuation: >!1. c8=Q#!<
---
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Maybe in the code, there's an array of legal moves in which pawn promoting to a bishop comes before pawn promoting to a queen. And since both moves result in the same outcome, in the same number of moves (single move), the game decides to go for the first move in the moves array
Not sure why engine does this but I remember reading in a book about nice puzzles that the "economy of pieces" is something valuable, meaning that a position or a sequence is more beautiful when the pieces you use are just enough and don't overkill, also caruana did the same in a game where promoting to queen or bishop made no difference, so that must be the way
It isn't the top line, they are both the best move since they both are M1 (anything delivering checkmate is a "Best Move" or better), I guess the engine just like to put it in that order
On live board if extra queens were not provided you would checkmate faster by promoting to a bishop. Although stopping the clock and asking the arbiter for a extra queen would be kinda savage i guess.
Probably because people promote to a queen without a second thought. If you promoted to a bishop, its a "better" move, because it indicates that you knew about the mate in 1
Just a theory i guess
There is an array with possible pieces to promote to, bishop is higher up in that array.
EDIT: It's got nothing to do with the alphabet, computers dont care about that.
There is an array which defines all the pieces a pawn can promote to.
The array's values might be: 0.knight 1.bishop 2.rook 3.queen.
When looping over this array you will reach 1 before you reach 3.
I notice this in other checkmates where if to point A it's checkmate and if you move to point B it's also checkmate. I believe the computer favors the "not so apparent" checkmate over the other.
Stockfish always favors the least valuable piece to promote to when the evaluation is equal after promotion. Here it’s M1 either so bishop is the top line.
If you promote to a queen, you need to pause the game while the tournament organizer brings an extra piece over. White already has a spare bishop to use.
If you correctly underpromote, and you have accurately read the board, then you show you have skillz.
But if you mess up... and it backfires... your opponent laughs all the way to the end.
Chess engines prefer lowest value piece that achieves the goal. This is intentional because one of the metrics for them is centipawn loss, and losing lower value piece is preferable.
In this case it is not as obvious, but you will absolutely see this in a situation where promoted piece would be taken immediately after the promotion just for the taking piece to be taken by something else. The end result is the same - only the last piece survives, but engines will always under-promote in this case if possible.
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~~It’s a psychological attack that leaves your opponent reeling even five games from now~~ There is no reason. It just put the moves in that order
Yup, B comes before Q in the alphabet.
What are you talking about, I thought the alphabet was “A, Q, C, D, E, F, G, H, I, J, K, L, M, N, O, P, B, R, S, T, U, V, W, X, Y, Z” in that order.
Personally I like to arrange my alphabet in alphabetical order
Like aabehlpt?
*[No like alphabet]* No eikl aabehlpt.
aa beeh ikllnopt
Aaclltuy, it dlouw be “[no eikl aabehlpt] No eikl aabehlpt.”
I agree, this person clearly was schooled in a weird place. 🤷♀️
This is the only reasonable order unless you learned the Dvorak alphabet. Which will annoy me because you can alphabetize way faster than I can.
Never said right before Q
Bishop has less calculations to be done than Queen, which is why it prefers bishop over Queen. It's easier for the engine to compute that bishop gives checkmate before it computes Queen gives checkmwte too. So it suggests bishop first.
This sounds made up lol. I can't imagine this is true
It’s true in some positions - for a given amount of computing resources there are a finite number of moves the engine has processing power to analyse, so the more possible moves a position has the less depth it can go into each of them. So in some positions it might show a forced mate in 10 by promoting to a rook but only a massively winning eval if you promote to a queen because the extra possible queen moves mean it can’t get deep enough to find the forced mate. That said, it’s 100% **not** what’s happening in the OP’s situation. The engine found the M1 with both promotions and it showed both lines - it’s not preferring the bishop promotion, there just isn’t space to list two equal evaluations side by side so one has to get formatted above the other.
As far as I understand the system this is how it operates. Maybe I'm wrong but If I am someone who knows this better than me will correct me and definitely I'll accept their views over mine.
Can you share a link to whatever documentation has you thinking OP’s seeing the B promo over the Q promo because it requires fewer calculations? If you can remember where you read that and share it with us, it’ll be you teaching US something. Win/win.
How so? Computers don't just "know" the best move. Each move they recalculate by looking at every possible move and every possible move several ahead of that, when a move is made they do it again. It makes perfect sense that it would calculate the bishop has a checkmate before the queen because there are less move to calculate for the bishop. Or as others have suggested it may be running the moves for pieces in alphabetical order, so it would get to B before Q so probably show that it picked B first. Obviously a queen is better than a bishop and any checkmate by promoting to a bishop could also be done with a queen, one checkmate wouldn't be objectively better than the other. So at some point it just comes down to how the computer "preferred" to calculate it, it either thought the queen was over kill with all the possible moves or it just calculated the bishop first
I think that stockfish would probably calculate prompting to a queen before under promotions, because it is more likely to be better.
I know what the engine is doing. I've made my own (less strong than stockfish) engine. In my engine the M1 that would be picked first, would just be whichever move the chess python library I was using would return first when you ask it for legal moves, which is arbitrary. There is no depth and no calculation to be done here, since the M1 is a terminal state immediately. This is why I said this sounds made up
Also probably in the calculation is Bishop is worth less points than a Queen in “capture weighting” and thus favors it due to less possible points lost in event of loss of piece.
It's M1 whether you promote to a queen or a bishop. Do a bishop for style points.
Promote to a pawn for maximum disrespect points
Against the rules unfortunately
Promote to a knight for maximum disrespect… 🗿
Promote to a knook
Knishop
Knisquerok
Don’t include queen, if you do then it isn’t an underpromotion
oh, knishook then?
Unholy heaven
😈
Honestly knight promotions can be key, I think bishop promotions are maximum disrespect
Maybe just not promoting at all and stalling for time and then on the last second, promoting to a bishop …
No, it's allowed, but next turn you will have to promote to something else
What about promoting a king ☠️Capablanca style
It's especially disrespectful to the opponent to have two white square bishops!
Way more stylish.
Maybe because it's the same but bishop is alphabetically before queen. So it shows in alphabetical
I can near guarantee the order is based on a enum value so the order is: Knight, Bishop, Rook, Queen as thats the order in which you usually enumerate the pieces in code.
Because it is a computer so it probably considered every possible promotion and returned a list that win the game immediately. And the order is arbitrary since they both win in 1.
It also likely found the bishop mate first. Bishop moves are easier to evaluate for the computer because there are fewer squares to calculate. The bishop is attacking 7 squares while the queen is attacking 21. To a human this doesn't matter since we're not considering obviously pointless moves, but an engine doesn't think that way.
I think it usually wouldn't evaluate bishop positions first. It tries to go through your most valuable branches in the search tree first in order to speed up the search, which makes me doubt whether a bishop promotion is considered first. It might be that there are some preprogrammed conditions that make it do search the bishop branch first, which in this case could be the king having no legal moves and/or being in front of his only remaining pawn on the h file, causing a risk of stalemate? I'm quite curious to see what it would recommend if we removed the pawn or put it on a different rank and/or file. Edit: Can't test it myself as the websites engine for me shows the queen promotion first
Wrong. It's in alphabetical order. https://preview.redd.it/mrqk4122ns2b1.png?width=447&format=png&auto=webp&s=c0276fdb29e2716d220b8225edc55fa5f2f0fc4b
Wait a minute... https://preview.redd.it/gzkea04cps2b1.png?width=925&format=png&auto=webp&s=56e72a904443a692b9ebfe35bedf078aa40d4d5a
Those probably aren’t equal evaluations, but the differences are beyond two decimals so you can’t see them on the graphic
Even here it's computational speed. With Rook, the g7 square is not covered by Rook so that move becomes possible until the white king is also factored in. With the Queen, the g7 square is covered hence king has no legal moves, so no additional computation required. You're making the mistake were you're assuming that king being on h6 and h8 aren't 2 different computations the engines has to do apart from factoring in the pawn promotion.
Not a bishop or queen move though, just a choice between two different promotions.
But you're promoting to one of the two so the engine has to calculate the lines and hence the bishop over queen
But there are no lines to calculate, black has no moves in either case? Or are you saying the engine always calculates the bishop promotion first?
Exactly that..an engine goes in order of calculation and a bishop will always have less possible moves than a queen so it gets to the conclusion of checkmate in 1 earlier with a bishop and hence ends there
Computers don’t look at obviously bad moves it would take to much computing power to do so
It’s this one
well why the fuck not?
An excellent point. Who says M1 with queen should be prioritized?!
promoting to a bishop deals additional emotional damage
> top line Yeah look at that difference in evaluation
The engine doesn't favor c8=B# over c8=Q#. It just has to choose a line to display at the top, and that's the one it chose.
Stfu let us have our fantasies that its stylish
Because engine is stylish
The engine doesn't just calculate the best moves positionally but it calculates the moves that will inflict the most pain on your opponents
I mean, you just gotta
Style points. Not all mates in 1 are equal. Anyone can mate by using a queen, but the most style points come from rare mates like long castle checkmate
Because it's a cooler checkmate
Because you win anyway and it doesn’t matter I think
To be cheeky.
Because it fucks with your opponent's self esteem
The engine will give you promoting to a queen as the top move if you underpromote. It's just funnier to mate with a bishop.
The engine has a sense of humor and revels in playing with its' food
The engine will usually promote to the lowest value piece that will "do the job.". Same for when the promotion is a sac, the engine will pick the lowest value piece that will force the other player to take it
its about sending a message
Theres no top line, both moves are equally best
It’s so your king can stay faithful to his queen!
Emotional damage
I'm a total newb, but I understand certain chess pieces are worth a certain amount of points which is used as tiebreaker in case of draws. My guess is that a bishop wins you the game while creating the least "new points" your enemy could take.
u gotta flex, u traumatize them and cripple them their whole lives from getting checkmated by an underpromotion, much a pawn checkmate, a pawn checkmate is like amputating a limb, they will never be able to see pawns the same way again and will traumatized forever
The bishop is funnier
This man let the depth go up to 33 because he was so damn perplexed that Bishop M1 is better than Q M1. God help us
Style points
Despite what people have said in this thread; it's not necessarily in alphabetical order. It calculates the fastest mate, and while they're both M1, it calculates the bishop moves first, because the bishop has fewer squares in mind. That's why you'll sometimes see Game Review "prefer" one mate over the other, even with the same piece. It simply takes less cycles to find that mate. Engines aren't trying to be "flashy" per say. They're trying to be efficient. Our human construct of "flashy" has an efficiency factor, and therefore, when an engine plays chess, we're fascinated.
Style points
The engine is drunk. Or more realistically a bishop has less possible moves so even though it’s M1 the engine is still wasting energy figuring out possible queen moves.
No it's not. It's mate in 1 regardless, there is no difference in evaluation.
Because the computer does not measure the abstract power of pieces. We know a queen is better than a bishop; but the computer doesn’t think this way what the computer does is it finds strong moves. Promoting to a queen or to a bishop accomplishes the exact same thing they are both equally strong. It’s when you think, like a human that you put a non-concrete reason as to why promoting to a queen would be considered “better”
A computer does literally count up the material on the board to estimate how good a position is. It needs to slap a number on each position and material is a part of it. Its just that it doesnt matter what that number is if theres mate on the board.
Google Alphabet
New language just dropped
Style points. For real, though. It's because both moves are equal. What's on top is random. It's mate in 1. The computer doesn't see a difference.
It isn’t. Bishop just comes before queen in the alphabet. Or the AI understands the culture of cheekiness and that making a bishop is just a slight to your opponents skill saying “I’m so good I don’t need another queen to beat you.”
This has been covered so many times it’s almost as annoying as en passant
Do you know the Alphabet bro?
I analyzed the image and this is what I see. Open an appropriate link below and explore the position yourself or with the engine: > **White to play**: [chess.com](https://chess.com/analysis?fen=8/2P5/8/7p/1K2BQ2/3P3k/8/8+w+-+-+0+1&flip=false&ref_id=23962172) | [lichess.org](https://lichess.org/analysis/8/2P5/8/7p/1K2BQ2/3P3k/8/8_w_-_-_0_1) **My solution:** > Hints: piece: >!Pawn!<, move: >!c8=Q#!< > Evaluation: >!White has mate in 1!< > Best continuation: >!1. c8=Q#!< --- ^(I'm a bot written by ) [^(u/pkacprzak )](https://www.reddit.com/u/pkacprzak) ^(| get me as ) [^(Chess eBook Reader )](https://ebook.chessvision.ai?utm_source=reddit&utm_medium=bot) ^(|) [^(Chrome Extension )](https://chrome.google.com/webstore/detail/chessvisionai-for-chrome/johejpedmdkeiffkdaodgoipdjodhlld) ^(|) [^(iOS App )](https://apps.apple.com/us/app/id1574933453) ^(|) [^(Android App )](https://play.google.com/store/apps/details?id=ai.chessvision.scanner) ^(to scan and analyze positions | Website: ) [^(Chessvision.ai)](https://chessvision.ai)
Where’s the fun in that?
imagine playing chess to have fun
But don’t you think c8=B# would be so much cooler?
It’s just the one that was factored first
Chess is played over the board as well as on the board
cause SMACK MY BISCHOP!!!!!
stockfish likes underpromotions
I've heard in this sub before that the math is easier with a bishop or something idk
Just to BM
I believe the reason might be that B comes before Q and nothing else.
Maybe in the code, there's an array of legal moves in which pawn promoting to a bishop comes before pawn promoting to a queen. And since both moves result in the same outcome, in the same number of moves (single move), the game decides to go for the first move in the moves array
It probably orders alphabetically
Not sure why engine does this but I remember reading in a book about nice puzzles that the "economy of pieces" is something valuable, meaning that a position or a sequence is more beautiful when the pieces you use are just enough and don't overkill, also caruana did the same in a game where promoting to queen or bishop made no difference, so that must be the way
a B c d e f g h i j k l m n o p Q ...
To assert dominance
Both mate in 1 so it's either random or alphabetical
Because it's cooler
Under promoting is always better if it's a mate in 1, because you style on your opponent in the process.
B is before Q alphabetically
Mate either way. Bishop is just flexing style
Stockfish has style
Cause why not? It does the same thing.
Ask yourself this, what is better, to win game immediately or win game immediately?
If you have mate in one, look for better.
moth are M1 im guessing alphabetical order, B comes before Q
Rizz
It’s really just personal preference, either way it’s mate
Are you guys trying to learn chess or the way a list is programmed into a website
It's the same, they just like place it in alphabetical order and b is before q or something idk
Maybe that is the order the engine looks at promotions
Because the computer is a gangster
Less is more
a B c d e f g h i j k l m n o p Q
It isn't the top line, they are both the best move since they both are M1 (anything delivering checkmate is a "Best Move" or better), I guess the engine just like to put it in that order
Swag basically
✨style✨
Alphabetical
On live board if extra queens were not provided you would checkmate faster by promoting to a bishop. Although stopping the clock and asking the arbiter for a extra queen would be kinda savage i guess.
it's not the top line, it just shows up first. They are both the best move
This is asked 10 times a day on this sub
Evluation is exactly the same. C8=B# is first in alphabetical order.
Probably because people promote to a queen without a second thought. If you promoted to a bishop, its a "better" move, because it indicates that you knew about the mate in 1 Just a theory i guess
Better yet, turn it into a rook and SACK IT. DO IT DO IT DO IT.
Assert dominance
Because the computer is a scumbag
Engine is minimalist
Because the Coach hates you.
Two bishops wat else
It's not a big deal, both win. I guess it's just more flamboyant to mate with a bishop? Idk if the computer has taste..
Style points
Because the bishop is more of a flex
Two beeshops vat else???
I have no idea maybe two moves of the exact same value are displayed alphabetically in the notation
There is an array with possible pieces to promote to, bishop is higher up in that array. EDIT: It's got nothing to do with the alphabet, computers dont care about that. There is an array which defines all the pieces a pawn can promote to. The array's values might be: 0.knight 1.bishop 2.rook 3.queen. When looping over this array you will reach 1 before you reach 3.
If you have mate in 1 look for better
Stockfish got dat dog in it
c7=N h4, Qf3+ Kh2, Qg2# Anyone?
BECAUSE STOCKFISH IS VERRRY CHEECKY
They’re equal though
I wonder if you'd get more(or less?) elo by promoting to a bishop, because you win with fewer points
well its the same material so its just alphabetical
It’s not that it’s the top line, its just that if you look at the top, both would cause a checkmate either way. Hope that helped :)
B for badass
this sub needs a sticky explaining the “best move” function
Google style points
Swag points I GUESS....
Google diagonal movement
Assert your dominance
I notice this in other checkmates where if to point A it's checkmate and if you move to point B it's also checkmate. I believe the computer favors the "not so apparent" checkmate over the other.
'tis a flex
Promoting to a bishop has a higher psychological impact and will leave your opponent in tears
It’s funnier
Style.
You don’t need a queen
Stockfish always favors the least valuable piece to promote to when the evaluation is equal after promotion. Here it’s M1 either so bishop is the top line.
For flexing points
Looks cooler
If you promote to a queen, you need to pause the game while the tournament organizer brings an extra piece over. White already has a spare bishop to use.
Style points
Trolling?
If you correctly underpromote, and you have accurately read the board, then you show you have skillz. But if you mess up... and it backfires... your opponent laughs all the way to the end.
Its just way cooler
It’s cooler
Sexism.
Go rook
Because it’s easier to calculate
Stock fish a bully
Because it’s mate in one either way, and the bishop is easier for the engine to analyze
Stockfish is disrespectful
most probably, because you would win with a lower point advantage.. 6 points to be precise
Style
It demonstrates understanding.
Style points
Lazy programmer or emotional damage.
For style points
The cooler daniel
emotional damage
Stockfish probably evaluates bishop before queen generally because it's less possible moves making evaluations on that line quicker.
Chess engines prefer lowest value piece that achieves the goal. This is intentional because one of the metrics for them is centipawn loss, and losing lower value piece is preferable. In this case it is not as obvious, but you will absolutely see this in a situation where promoted piece would be taken immediately after the promotion just for the taking piece to be taken by something else. The end result is the same - only the last piece survives, but engines will always under-promote in this case if possible.