[HN Gopher] The rarest move in chess [video]
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The rarest move in chess [video]
Author : ca98am79
Score : 80 points
Date : 2024-06-10 18:50 UTC (4 hours ago)
(HTM) web link (www.youtube.com)
(TXT) w3m dump (www.youtube.com)
| ViktorRay wrote:
| This video is excellent. It's one of those videos that will
| become a classic of YouTube in the future. The kind that's
| recommended to millions of people
| skilled wrote:
| Watched this earlier today myself, fantastic work by the author.
| AnimalMuppet wrote:
| "doubly disambiguated bishop capture checkmate"
|
| It's a 30 minute video. If you care that much about the topic,
| enjoy. If you just wondered what the move was... you're welcome.
| f154hfds wrote:
| It's a 17 minute video.. that's quite the round up. Just saying
| because for me the difference from 15 minutes to 30 minutes
| tends to go from: "yeah I'll check this out" to "boy this is an
| investment".
| AnimalMuppet wrote:
| Huh. I stand corrected. Not sure where I got 30 from.
|
| (I wasn't rounding that far, I was giving what I _thought_
| was an accurate number. Accuse me of bad info, not bad math.)
| LeifCarrotson wrote:
| Interesting, I'd assumed it was going to be a pawn promotion to
| something esoteric like a knight that didn't create a check,
| but that's a couple layers deeper.
|
| Thanks for the TLDR.
| shric wrote:
| The creator admits it early on -- it's measuring rarity based on
| the specific notation everyone uses, which greatly influences the
| classification of rarity.
|
| Fundamentally all chess moves are a piece moving from one source
| to another destination including:
|
| - castling as a king move with a distance greater than 1
|
| - pawn moves to the 8th or 1st rank with the additional datum of
| a new piece
|
| - en passant is the same as a regular pawn capture, it just
| requires the victim pawn to have moved two squares previously.
|
| Algebraic notation also has an arbitrary and reasonable amount of
| extraneous detail despite dropping the source location if it's
| unambiguous.
|
| For example, the captures (x), check(+) and checkmate(#) symbols
| are all unnecessary given the previous state of the board is
| always known. With en passant it's also unnecessary to have a
| special symbol indicating an en passant capture, and indeed there
| isn't one.
|
| I was initially hoping to get some insight on e.g. which pairs of
| squares had the fewest moves for a given piece etc.
|
| That being said, I thoroughly enjoyed the video. It was
| beautifully illustrated and explained everything clearly.
| kristopolous wrote:
| Right, you'd need to look at board state transitions as opposed
| to move notation.
|
| I'd imagine remarkably foolish moves from board states that
| only quite sophisticated users would get to would be up there
| jerf wrote:
| "I was initially hoping to get some insight on e.g. which pairs
| of squares had the fewest moves for a given piece etc."
|
| This may not be quite what you were asking for, but it's close,
| and has the advantage that I can link it right now. Tom7's Elo
| World chess video has where pieces start and end up, and their
| survival rates, as a chart:
| https://youtu.be/DpXy041BIlA?si=Zdh6Rh6mekatp2-q&t=815
| bobmcnamara wrote:
| Funny enough, en passant is the only capture that takes a piece
| not in the destination square.
| Dylan16807 wrote:
| That's arguable. The motivation for the rule, and especially
| the name of the rule, suggest the pawn is not all the way
| there yet.
| CrazyStat wrote:
| In what sense is the pawn not all the way there? It
| occupies the square, prevents any other piece from
| occupying the square, can deliver check or checkmate from
| the square, and can be captured on the square.
| Dylan16807 wrote:
| In the sense that a pawn that's in the perfect position
| can strike while it is "passing", but if that doesn't
| happen then it finishes the move and it's too late, the
| opportunity is gone forever.
| Someone wrote:
| The OP refers to the fact that "en passant" is french for
| "in passing", so the move sort-of refers to the idea that
| the pawn takes the other pawn while it is passing through
| the third or seventh row, as if the capture starts while
| the previous move still is in progress.
|
| Also, the pawn can't deliver checkmate, can it, if it can
| be taken en passant? It probably is possible to construct
| a position where taking en passant would bring the king
| into check in another way, but in those cases, the en
| passant move isn't possible.
| Supermancho wrote:
| Idioms do not have to be interpreted as literal, so I
| don't understand why anyone would think this. As I
| understand it:
|
| https://lichess.org/editor/rnbqkbnr/pp3ppp/8/3pp3/2pPP3/4
| K3/...
|
| the King is never in check, for the purposes of the game.
| The piece removed isn't in the destination square.
| bongodongobob wrote:
| It's because pawns used to be able to move only one
| square. En passant was created when they were allowed to
| move two squares, sort of pretending that it only moved
| one square and is why you can only do it immediately
| after the first pawn move, kind of where the pawn
| "should" be.
| anikan_vader wrote:
| Some sources do write ep after en passant captures. As you
| point out, it's no more redundant than notating checks.
| Sesse__ wrote:
| Notating checks is not even redundant; it can disambiguate
| which piece is to move without additional information (e.g.
| Rac1 and Rhc1; only one of them might give a discovered
| check, so Rc1+ could then be an unambiguous notation where
| the check is not redundant). The PGN spec is clear that SAN
| disambiguates legal moves and not pieces (if moving one of
| those rooks would put yourself in check, you should not
| disambiguate when you move the other one), but I don't know
| whether it considers the check part of the move for those
| purposes.
| Retric wrote:
| He did find a move that occurred a single time including the
| specific game that included it. He also showed many moves that
| occurred zero times from every single game played on
| lichess.org.
|
| So, depending on your definition either could reasonably
| qualify. No matter the unanimous notion, many moves have never
| been played and some have been once. Which you pick as the
| rarest is simply an arbitrary definition.
| kristopolous wrote:
| His definition of rare is an artifact of the notation where board
| state requires disambiguation, as in it includes externalities.
|
| I feel like the question remains unanswered
| thih9 wrote:
| A different take on rare chess moves and perhaps more rare than
| what is presented in the video:
| https://en.wikipedia.org/wiki/Joke_chess_problem
| paxys wrote:
| The problem with using a dataset consisting of _all_ games on
| lichess.org is that most /all instances of these moves are most
| certainly from people who are trying them out in a noncompetitive
| game just to see what happens. In fact he himself likely polluted
| the data further just to make this video, maybe even enough to
| change the answer.
|
| There needs to be a minimum bar for the data to be meaningful,
| e.g. by restricting to players above a certain rating threshold,
| or considering tournament games only.
| shric wrote:
| He stated that he tried using master tournament games but the
| dataset was way too small.
|
| But yes indeed, the single example game he showed was indeed a
| result of the winner playing very silly moves and the loser
| allowing it rather than resigning.
| antaviana wrote:
| In bullet games at Lichess it is not that uncommon to play on
| lost positions to try to either flag the opponent or to
| offload as many own pieces as possible to seek a stalemate
| with the frenzy. Conversely, the winning side then tries to
| delay the win by promoting a bunch of unneeded pieces and
| sort of demonstrating who is really in charge. It's even fun.
| CalChris wrote:
| Did he include under-promotion captures resulting in zugzwang? If
| you're not including zugzwang then you shouldn't include checks
| and mates. The problem becomes a lot simpler.
| bitcurious wrote:
| Fun video. An interesting follow up would to do this would be to
| 'disambiguate' every move, such that a move was a single piece's
| movement and reflected less of the state of the game.
| elijahbenizzy wrote:
| This is delightful. I think that the hardest part (that,
| honestly, he absolutely nailed) is defining "rare" and "move" --
| not only did he come up with reasonably satisfactory definitions,
| but he also was able to walk us through his discovery process.
|
| The rest is a fun programming problem (which he largely glossed
| over), and it's clear he put a massive amount of care into the
| video. Thank you!
| none_to_remain wrote:
| Do chess players actually consider this "double disambiguation"
| from the notation to be a different "move"?
| bongodongobob wrote:
| No.
| billforsternz wrote:
| This video is really about the rarest Standard Algebraic Notation
| (SAN) corner cases, which is more than a little different from
| rarest moves. But the author basically acknowledges this, and
| 'rarest moves' is so hard to really define anyway. So kudos it's
| otherwise a great video.
|
| I'm about equally impressed with the statistical analysis and the
| video construction and presentation. I can imagine tackling the
| former, but not the latter. I did notice a few mistakes in the
| video presentation though (eg a Bd4# that he presented as Be4#).
| I imagine at some point he just thought "I've polished this thing
| enough" and stopped.
| pimlottc wrote:
| The game and move in question is here:
| https://lichess.org/NoXEwGi8#136
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