[HN Gopher] Los Alamos Chess
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Los Alamos Chess
Author : nanna
Score : 150 points
Date : 2024-04-02 09:15 UTC (13 hours ago)
(HTM) web link (en.wikipedia.org)
(TXT) w3m dump (en.wikipedia.org)
| Y_Y wrote:
| 1. Feynman to U-235
| jhbadger wrote:
| I'm not sure if anyone actually plays this as an actual chess
| variant, but it is fun to write a chess player for this,
| mirroring the 1956 version. I remember reading about this in the
| 1980s and wrote a version in BASIC that could beat me every time
| (maybe not that impressive objectively, but it impressed me).
| passwordoops wrote:
| For some reason your comment made me think of the classic
| Simpsons bit, "When I stamp your foot and say 'Hello Mister
| Thompson' you say hi back." Funny how the human mind works
| huytersd wrote:
| I hate sudoku variant videos that rope me in with some
| impossible scenario and then explain a totally different set of
| rules.
| moffkalast wrote:
| > This program was written at Los Alamos Scientific Laboratory by
| Paul Stein and Mark Wells for the MANIAC I computer
|
| I see the names of computers have gone significantly downhill
| since the 60s.
| kijin wrote:
| > Metropolis chose the name MANIAC in the hope of stopping the
| rash of silly acronyms for machine names [1]
|
| Looks like even MANIAC was deliberately restrained to make it
| sound less maniac than the names of computers that came before
| it. Can't beat Manchester Baby, Colossus, The WITCH, SWAC and
| MADDIDA.
|
| Being Los Alamos, they really should have named it ATOMIAC or
| something.
|
| [1] https://en.wikipedia.org/wiki/MANIAC_I
| moffkalast wrote:
| ATOMIAC is a great option, but if you look at today's super
| computers it's all Sierra, Selene, Summit, etc. Lame ass
| corporate names.
|
| I'm at least glad my university lab named their main GPU
| server The Crushinator.
| davidw wrote:
| > The computer still needed about 20 minutes between moves.
|
| Wow. Coding and debugging that is... a whole other level of
| difficulty compared to coding these days.
| pacaro wrote:
| My mother describes laying out the program flow on index cards
| (or recycled punch cards depending on what was available) on
| the living room floor and walking through the program/room with
| a notebook tracking the program state.
|
| To her that was debugging
|
| This was mid to late 60s
| davidw wrote:
| That's pretty cool! You should get her to write it up so it's
| not forgotten.
| tombert wrote:
| Every time I read about about how slow _really_ old computers
| were, I say an internal "thank you" to Bell Labs for the
| transistor. I'll occasionally see a YouTube video about vacuum
| tube or relay based computers, and they'll show their
| operations on the order of 3-10 operations per second. And here
| I am writing this comment with something whose operations are
| on the order of _billions_ per second.
| kevindamm wrote:
| ...and that's not all! With access to our modern network you
| effectively have Teraflops at your fingertips, possibly even
| Petaflops if you know what you're doing.
| ForHackernews wrote:
| Thank god, because I can `npm install` in mere minutes and
| run two, possibly even three Electron apps concurrently.
| FredPret wrote:
| He said petaflops, not exaflops
| dvh wrote:
| Kruskal (author of the kruskal algorithm) won.
|
| edit: pardon, wrong Kruskal
|
| Joseph Kruskal had two notable brothers, Martin David Kruskal,
| co-inventor of solitons, and William Kruskal, who developed the
| Kruskal-Wallis one-way analysis of variance. One of Joseph
| Kruskal's nephews is notable computer scientist and professor
| Clyde Kruskal.
| pavel_lishin wrote:
| And apparently his mother popularized origami in America!
|
| https://en.wikipedia.org/wiki/Lillian_Oppenheimer
| thriftwy wrote:
| This one seems to be the author of
| https://en.m.wikipedia.org/wiki/Kruskal-Szekeres_coordinates
|
| Which are great at challenging commonly held beliefs about
| black holes.
| AdmiralAsshat wrote:
| So judging from the omission of the bishop and the queen, the
| computer really hated calculating diagonals, huh? I would've
| assumed that calculating the knight's movements would've been the
| bigger headache.
| InitialLastName wrote:
| The queen is there. It was probably a more interesting game to
| keep the knights for their moveset rather than keep the bishops
| (given the need to reduce to 6x6).
|
| Between the ~half-sized board, the intrinsic limitations in
| where they can go, and the reduced pawn movement, bishops would
| be very clumsy if left in.
| Sharlin wrote:
| I don't think there's anything difficult in calculating a
| knight's moves. On the other hand rooks, bishops, and queens
| generate many moves at a time, making the game tree much wider,
| which _might_ make a difference, or it might not. But anyway,
| as noted by the sibling, queens were there (except in the
| second game, in which _Kruskal_ played without and the computer
| played with, to even the odds), and the omission of bishops in
| particular had nothing to do with evaluation difficulty per se.
| Sesse__ wrote:
| Humans are probably worse with knights than any other piece,
| relative to computers. Queen is a possible second; queen
| endgames are super-complex for humans since there are so many
| options and very few of them can be easily pruned. (I guess
| you can say that humans are bad with knights and computers
| are good with queens, especially endgame queens.)
|
| Diagonal sliders do create lots of headaches for bitboards,
| but those were not used for chess before 1967 or so, i.e.,
| more than a decade later. Generally one uses magic bitboards
| today (basically a perfect hashing technique to extract the
| bits of the diagonals a piece can attack into a neat little
| linear bit line), but they depend on fast multiplier and a
| fair amount of RAM for LUTs, which would of course not have
| been available on the MANIAC. I would assume that MANIAC just
| looped over all possible moves in the move generation phase.
| Sharlin wrote:
| Thanks, interesting!
| silisili wrote:
| They retained the queen, it was just the human played without
| one against the computer for some reason. Probably to give
| MANIAC a fighting chance.
| OscarCunningham wrote:
| Has this been solved?
| bongodongobob wrote:
| No, we only have endgames solved up to 7 pieces. 24 pieces is
| waaaay too big to solve.
| tbrake wrote:
| 24 pieces on an 8x8 is a nightmare, sure.
|
| However, other smaller chess versions (e.g. 5x5 w/ 20 pieces)
| are at least weakly solved and given the piece/pawn/move
| restrictions of this 6x6 variant, I wouldn't be surprised if
| a weak solution here is possible as well.
| bongodongobob wrote:
| I would be. At a minimum you've got 16 moves the first
| couple moves. There's no way.
| Sesse__ wrote:
| We can do a rough estimate.
|
| There are (_very_) roughly half as many squares in 6x6 as
| there are in 8x8. This means that for every piece you add,
| you can expect (again very roughly) a 50% bonus to your
| branching factor. Now look at the best tablebases currently
| available (Syzygy):
|
| Up to 5 pieces: 1GB Up to 6 pieces: 151GB Up to 7 pieces:
| 17277GB
|
| So, let's assume the factor of 140 per extra piece; of
| course this doesn't hold perfectly, but still:
|
| Up to 8 pieces: 2418TB Up to 9 pieces: 338PB Up to 10
| pieces: 47320PB
|
| Now divide that last number by our 2^10 bonus. That leaves
| 46PB for 10-piece tablebases. We were asked for 24-piece.
| This is unlikely to go down well.
|
| Of course, there will be some small additional bonus for
| the fact that fewer positions are possible (easier to be in
| check), double-pawn-push doesn't apply, no en passant or
| castling to worry about, and fewer piece types. Still, it
| honestly doesn't look that good. :-)
| tbrake wrote:
| I'm really only interested in weakly solved, i.e. "forced
| draw from starting position" like the 5x5 variant, not a
| perfect play tablebase from all possible positions.
|
| Given that 5x5 is (weakly) solved, even though your rough
| estimates would put its 20-piece 5x5 starting position
| outside the realm of possibility, I don't think you're
| discounting accurately how much a reduced
| board/piece/ruleset can affect those exploding
| permutations for 6x6 as well.
| Sesse__ wrote:
| Well, it helps if you can meet-in-the-middle, roughly.
| And it helps a _lot_ to do a weak solve, i.e., you don't
| care about winning won positions, only showing a draw
| with perfect play.
| thethirdone wrote:
| Your analysis would pretty similarly apply to 5x5
| Gardner's chess which has been weakly solved. Simple tree
| search can be quite effective as the branching factor is
| cut down a significant amount (2x in the starting
| position). Gardner's chess was completely solved without
| any tablebases.
|
| It is only an argument against building a complete
| tablebase. Additionally because the extra space is
| reduced the high piece count version is likely the be
| much smaller than this would predict because pieces
| cannot overlap.
|
| Just looking at the piece positions without regard to the
| types shows a better than 2x relationship for tablebase
| size.
|
| (64 choose 7) / (64 choose 8) ~ 10% whereas (36 choose 7)
| / (36 choose 8) ~ 25%
|
| Additionally, because the tablebase would need to go past
| 18, the possible piece positions would actually shrink.
| To be clear, the tablebase would not shrink because of
| the piece types.
| Sesse__ wrote:
| I'm not sure if you can call it "completely solved" if
| it's only weakly solved, but sure. It's a different goal
| (and my answer was a response to a "can't we just build a
| tablebase" comment).
| zone411 wrote:
| Note that the number of possible legal positions will
| likely be largest with fewer than 24 pieces. For regular
| chess, I've calculated that there are most legal
| positions for 29 pieces:
| https://github.com/lechmazur/ChessCounter?tab=readme-ov-
| file...
| abound wrote:
| Not to be confused with Atomic Chess:
| https://en.m.wikipedia.org/wiki/Atomic_chess
| CrociDB wrote:
| > The computer played three games. The first was played against
| itself. The second one was against a strong human player, who
| played without a queen. The human player won. In the third game,
| MANIAC I played against a laboratory assistant who had been
| taught the rules of chess in the preceding week specifically for
| the game. The computer won, marking the first time that a
| computer had beaten a human player in a chess-like game
|
| I think this paragraph is kinda funny.
| ChilledTonic wrote:
| I'm actually very interested in picking this up as a varietal to
| regularly play; the smaller chessboard size and reduced pieces
| would (theoretically) result in faster, pickup play.
| prometheus76 wrote:
| 5 X 5 is also really fun. It's the queen side basically, with a
| row of pawns in front. So there's only one row of open spaces
| between the two sides. It really stretches my brain to play it,
| but has helped me get better at calculation for sure.
| csmeyer wrote:
| "Pawns may not be promoted to bishops;"
|
| ??????????
|
| For real, I would absolutely love to know why that constraint was
| needed. Does anyone have info on why?
| abricq wrote:
| This rule is required because "as in chess", a pawn may promote
| to bishop.
|
| If you only remove the bishops from the starting position, then
| the rules of chess still allow bishops to come in later in the
| game (through a promotion).
|
| I am assuming they did not have enough memory to hold the rules
| of bishops, and therefore decided to completely remove them
| from the set of possible pieces. They allow rooks and knights
| promotion because these pieces are in the set of initial
| pieces: their rules are already implemented.
| csmeyer wrote:
| Oh duh... well my question was not insightful but yes your
| answer makes sense, there are no bishops on the board lol
| billforsternz wrote:
| I don't know why you've put lots of question marks, surely this
| is completely understandable. The whole point of this was that
| real chess was too big and complex, hence this dramatically
| smaller simpler version. There's no bishops in the start
| position so there's absolutely no way they'd bother
| implementing the bishop underpromotion corner case.
|
| Amusingly enough Rybka, the top engine for many years
| comparatively recently didn't implement bishop underpromotion
| either. For a much different reason. The programmer chose a not
| so great low level bit representation convention that forbid
| representing this case. He refused to fix the error because it
| would be too much work for the more-or-less non-existent
| situations where promoting to a bishop is the best move.
| teo_zero wrote:
| Interesting. Does anybody have any example where a promotion
| to bishop would be preferable to Queen?
| Sesse__ wrote:
| Basically anything where a bishop would win, but a queen
| would put the other side in stalemate.
|
| For an extreme example, see
| https://en.wikipedia.org/wiki/Babson_task.
| rdlw wrote:
| An example from a real GM game:
| https://youtu.be/CBoS9hSM6oM
| billforsternz wrote:
| I'm at work so I'm not going to try and do some
| experiments, but my guess at relative frequency of
| (under)promotion being the best move (Queen = 1) is
| something like;
|
| Knight 1e-3 Rook 1e-5 Bishop 1e-7
|
| A complicating factor in measuring this is that often a
| rook serves just as well as a queen, the opponent is going
| to capture immediately anyway, so players sometimes
| underpromote to a rook just for the fun factor. My number
| is more meant to represent cases where underpromotion
| really is the best move. Knight underpromotion is by far
| the most important, because a knight can do things a Queen
| can't, most typically give check to keep a combination
| going without giving the opponent an opportunity to play an
| active move. Rook and Bishop underpromotions can only be
| advantageous when they simultaneously avoid stalemate and
| keep a winning advantage. This is much more likely with a
| rook, for example in the famous Saavedra position, perhaps
| the most famous chess problem of all (it featured as
| decoration on our wedding cake :).
| QuesnayJr wrote:
| If anyone wants to try playing this, it's one of the variants
| supported by Fairy Stockfish.
| cyberax wrote:
| I am disappointed because it doesn't involve nuclear bombs.
| kevindamm wrote:
| yeah, I was expecting chess piece variants like Fairy Chess..
| but there still can be! But do we add wind and fallout? Or make
| it a MAD type of thing where the meta-game is a kind of
| Prisoner's Dilemma? Either way, we could call it Manhattan and
| give it a go..
| hammock wrote:
| I was thinking spontaneous decay - at a random time every so
| often, one of your pieces may "decay" and be demoted, from a
| major piece to a minor one, or from a minor one to a pawn :)
| michaelcampbell wrote:
| Looks interesting as a total looker-on of chess. Does the smaller
| board and reduced rules make the game any easier?
| umanwizard wrote:
| Yes, that reduces the search space
| ryukoposting wrote:
| It makes the game go a lot faster, that's for sure. It lowers
| the barrier to entry by a lot, while still requiring the same
| modes of thinking.
|
| There are a ton of chess-like games out there that have small
| boards and play times of 10-20 minutes. IMO as an everyday
| thing to do with friends, they're a lot more fun than chess.
| mxwsn wrote:
| Any suggestions or favorites?
| ryukoposting wrote:
| Onitama for sure: https://en.wikipedia.org/wiki/Onitama
|
| It's played on a 5x5 board. You get two cards that tell you
| what moves you can make. Either card can be used with any
| of your pieces. Once you've used a card, it will end up in
| your opponent's hand a couple turns later.
|
| Every time you play, it's a little bit different because
| the cards are different. In addition to the chess-like
| thinking, there's a lot of strategy in learning when to use
| particular cards. Some cards are really powerful, and it's
| worth keeping them in your hand until the right moment.
|
| IME a single round of Onitama usually lasts 10-15 minutes.
| The shortest game I've played was probably about 6 minutes,
| and the longest was 30.
|
| It's simple enough that you can just pull it out and play
| with anyone, even if they've never seen it before. Pretty
| much everything you need to know to play Onitama is printed
| on the cards sitting right in front of you. It's pretty
| easy to pick up.
|
| It's also nice that you only have to clean up 10 pieces
| after a game instead of 32.
| ryukoposting wrote:
| This looks like fun. I like chess variants that use smaller
| boards like this. They offer much of the same high-level
| strategic thinking, but a much shorter play time and a lower
| barrier to entry.
|
| My favorite one is Onitama, it's actually quite different from
| chess but the same intuitions apply.
| frankfrank13 wrote:
| Found an example to play online with a bot!
| https://www.chessvariants.org/play/jocly/los-alamos-chess
| procgen wrote:
| I'd love to play against the original algorithm.
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