Saturday, August 09, 2025

Chess is solved (2025)

 Chess is 'solved' and it's a draw.

As in shown/discussed in my recent article on academia.edu:

An ('ultraweak') solution for chess

In 2007 dr Schaeffer wrote the academic paper: "Checkers is solved":
https://www.researchgate.net/publication/231216842_Checkers_Is_Solved

But with this (provocative?) title he 'only' meant that checkers was 'weakly' solved,
nevertheless this confirmed that with best play the game would end in a draw.

The situation (draw) is similar for chess, although not (rigorously/mathematically/
experimentally)  'proven' (yet). An 'ultraweak solution' (Allis et al) means that the theoretical
outcome of the game has been determined. And for chess that outcome is a draw.

Beyond all, or any ('reasonable') doubt. Last year, there were some -sometimes-
vehement reactions (and discussions)  on talkchess.com that this is not rigorously
mathematically proven; but that is irrelevant (i.e. doesn't matter) relating
'ultraweak solutions' according the definition (which is 'determining' the
theoretical outcome, not rigorously mathematically proving it). 
In the recent ICGA conference, Nov 2024,  the talk by Prof J. vd Herik (Leiden)
the topic of his talk was "our aim is to solve chess" (keynote 4):
https://icga.org/?page_id=3907

But from his -entertaining (but imho not always up to date_ presentation it becomes
clear he means 'weakly' solving.  And whereas he previously estimated around the
year 2035 for such a result, he now delayed that to approx. 2060 (whereby
dr Schaeffer is even more skeptical and predicts 'not until  2100...).

In this respect, first of all some background about solving games:
https://en.wikipedia.org/wiki/Solved_game

So my narrative is different, and i claim that the ultraweak solution for chess now
has been found; for the game of Hex, the ultraweak solution was found with
some strategic arguments, for chess i have used other methods (e.g. cumulative
evidence), but thereby i am convinced i have 'determined' the theoretical outcome
of the game (not only if both players play 'perfectly' but simply when they stay
within the drawing margin(s). Draw; beyond all ('reasonable') doubt.

In addition, because there are no foreseeable zugzwang situations in chess with 'perfect
play' (contrary to checkers and draughts, this also mean that we can predict the outcome
of a weak solution (draw). Although strictly spoken, this remains a 'conjecture';
but for me (and in my opinion also in reality) 100 pct true.
Example, the Goldbach 'conjecture' in mathematics (1) also hasn't been rigorously proven
(yet?); nevertheless it's (generally accepted to be) true (2). Also, in mathematics, there
exist (other) truths which cannot be proven (Gödel); so i don't worry about proofs.

At the end of my article (on academia) as given above, I mention as suggestion for
further research to first find  'weak' solution for international draughts (similar as for
checkers), which certainly is not impossible (but will require  more computing powers).
And only then for chess (as it will require vast computer resources). But the outcome
already is known by now (although Steinitz already claimed it end of 19th century):
it's a draw.

Small side note, in the article i refer to the 'perft' search on the chess programming wiki,
with perft meaning (engine or search) performance test; here's the contemporary research: 
https://grandchesstree.com/perft/0/results
Far from a weak solution, but analyzing the results will continue to show
that Black can always keep a draw; ergo, it's 'solved' and it's a draw.
Does this mean that computers have 'destroyed' chess: well far from that.

First of all, a weak solution wouldn't mean that the program knows the
best move for *every*  (imaginable) position, this would be a 'strong'
solution; and that has not even be achieved for Checkers.
Note the term 'weak solution' in game theory seems to come from
a(nother sort of) mathematical definition:
https://en.wikipedia.org/wiki/Weak_solution
In game theory it's a completely different thing, of course. But anyway it's important
to know that such a 'weak' solution (eg. draw) is not so 'weak' in principle, because it
means that the outcome of the game (with best play) is exactly known.
So checkers is a draw, (experimentally) 'proven' indeed (by Schaefer in 2007).
For chess we can argue, whether there is a (rigorous) proof (3), but this doesn't matter so
much, as for the 'ultraweak' solution it simply means that the theoretical outcome (with
best play) has been 'determined'.

Historically, it was thought that in chess the  first mover (White) has a slight advantage (4),
and most opening during the last century was also based on this (elusive, imaginary) idea.
Because with cumulative recent (eg. the last decade) evidence, it now has been been determined
that the outcome of a game of chess with 'best play' (or simply staying within the draw margin)
from the start position with free choice of opening/defense choice (White/Black) will be a draw.
Beyond any ('reasonable') doubt;  just like the Goldbach conjecture is generally
accepted to be true.  

Generally, it was thought that a solution for chess would 'destroy' the game, this is
not true of course (except for correspondence chess, and possibly, slow Fide chess.
On the contrary, the 'drawish' nature of the game opens up  complete new avenues
in opening theory, with (new) gambits, and so on (6). As for a  'strong solution' for
chess, it will be almost impossible to achieve, so there' s still (some) hope for
problem-chess (eg mate in x puzzles) aficionado's (and programmers, as well) :)

Note this draw 'problem' is already known for some times by top-engine tournament
organizers, like TCEC, where the games nowadays start with a set of unbalanced openings
(with free choice in opening play from the start); in ICCF correspondence chess it's a paradigm
change which is still ongoing, as here the organizers seem to be reluctant to adapt the
(eg possibly endgame) rules. 

Conclusion: Chess now (2025) has been solved, at least in the 'ultraweak' sense .
And the outcome  (with 'best' play) is certain (draw).

PS as for 'number crunching' projects aiming for a weak 'solution for chess with
similar methods as done for Checkers, as mentioned in my (academia) article, I
suggest to start first with international draughts, as e.g. discussed on talkchess.com:
Draughts has not been solved
But then anyway, for chess i don't think such a number crunching method is the right
approach. Instead, I advocate more theoretical research in game theory, exploring the
concept of 'balanced games' (with an equilibrium) and possibly proving (or at least
demonstrating beyond any reasonable doubt) that chess is such a 'balanced game'. 

References:

(1) https://en.wikipedia.org/wiki/Goldbach%27s_conjecture
and it's generally assumed to be true.
https://www.lesswrong.com/posts/iNFZG4d9W848zsgch/the-goldbach-conjecture-is-probably-correct-so-was-fermat-s
(2) While apparently there still is no official proof (like also for eg. the Riemann
conjecture) there exist already a lot of tentative proofs on youtube, probably
using one of these methods (but now i'm digressing from the original topic/chess...):
https://journalspress.com/LJRS_Volume21/Two-Ways-to-Prove-Goldbach-Conjecture.pdf

(3) solution methods  for (and progress with solving)complex problems in complex math (and thus game theory) are not as simple as eg.  as puzzle -or question- in a math Olympiad. According to Lakatos, the famous expert in the philosophy of mathematics, for  more complicated it's a gradual, complex process, almost like in physics (whereby in the latter situation a 'proof' of a theory would not be applicable and thus only falsification methods can apply (Popper): 
https://hps.elte.hu/~kutrovatz/LakatosEng.pdf
In chess the only -or at least best- falsification method to show that the (now in 2025 determined) 
'weak solution' would be incorrect, is  to find a forced, winning line for White, starting from the
opening position. But from modern opening theory we know this is impossible; a point of criticism
may be that not all opening lines have been explored, thus that there still may exist some
unknown opening lines, leading to an advantage. Because of such reasoning, I developed
decades ago a 'book correction' module in my program Bookbuilder (7). Thus later being able
to examine systematically the complete tree of opening move (although not brute force, at
least within reasonable alfa/beta bounds); and thus came to the conclusion there is not
fundamental opening advantage possible (to achieve) for White. A finding which later was 
corroborated with the billions of opening positions analyzed in the Chinese opening base,
by many different chess analysts. Thus there is no 'winning strategy' (Zermelo (5))
thus the game must end in a draw. Simple as that.

(4) First move advantage in chess

(5) To be precise, the theorem by Zermelo states that if there is a (forced) win for one side,
then there must be a winning strategy. And imo for the game of chess, such a (imaginary)
'winning strategy' would already start in the opening phase. But that's simply impossible,
such a strategy as the -by now exhaustive- analysis of modern opening has shown, simply does
not exist; it is not possible for White to gain an advantage in the opening phase.
Also easy to understand for anyone having sufficient experience with (correspondence)
chess and or (preferably) computer chess; if there is a balanced position, (evaluation
0.00 at sufficient depth) we know with the modern Nnue (neural network)
engines that there is no way that this one side can force a win (with sufficiently strong
defense by the other side), because of the relatively large branching factor in chess,
especially in the middle game. Thus, whereas in the past in some special situations
some 'Boa-constrictor' (Karpov) style of positional chess could be applied to squeeze
out a win in such situations, this nowadays simply is not possible anymore. 

(6) https://sourceforge.net/projects/chess-gambiteer/

(7) https://sourceforge.net/projects/Bookbuilder

PS in the above academia article I mention a Nash equilibrium, with this, strictly speaking, 

usually in game theory something else is meant (for multiple person 'players' with statistical
uncertainties) but the idea must be clear: there are balanced games, and if the players stay within
the drawing margin, there is -and remains- a static equilibrium  and the result must be a draw.
Question/thought experiment: what if with much deeper search in certain (rare)positions
it appears that it wasn't in equilibrium ? Answer, then one player has  not played 'perfectly'
i.e.  not good enough, i.e. not stayed within the drawing margin, and in a subsequent,
better game this can be avoided. Which again means that later games with
such knowledge (avoiding mistakes) will be drawn.
Discussion, the concept of a 'balanced'  (two person) game appears to be rather new
in game theory. Instead of a complete, exhaustive search within the tree, with this
concept it would be sufficient to 'prove' that chess is such a 'balanced game' (*). 
So far this of course has not (yet) been 'proved' , but at least it has been shown in
practice that this is the situation; which again corroborates the 'ultraweak solution'.
(*) this is highly plausible, because in chess, all pieces except pawns can move backwards,
contrary  to checkers (and draughts) thus, in combination with the 3 pos repetition-draw
rule giving a high 'degree of freedom' for both players and a relatively high draw margin.

Friday, February 07, 2025

New review (of my chess openings book) on Lulu.com

 Got a new review of my openings book (paper version), from Norway,
and as result now the overall rating is five stars:

        Paperback on lulu.com

Meanwhile i had made some important updates, and the above book now contains the
latest theory. And on Lulu it's cheaper than on Amazon (where it's also listed:

        Amazon version

(also five stars, other reviews)

The only chess opening book most players ever (will) need...


"gens una sumus"





Thursday, October 17, 2024

Update on Amazon

 now (the new edition of) my book (as on Lulu) also is available on Amazon again:

Better Chess Openings (paperback)

as found with latest Nnue engines (and minimax/backsolving with Bookbuilder).

The new bonus chapters at the end with 1.d4 are anti-Gruenfeld (3.f3)
and Catalan.

An update for Kindle probably follows later.

The only chess book about openings most amateur players will ever need.


Thursday, September 26, 2024

New edition of chess (opening) book

 Just finished a new edition of my (paperback) book

'Better Chess Openings' 

(from beginners to advanced, in different sections).

available at Lulu

The only book which nowadays covers most of all modern opening theory
(based on 'nnue' top engines and other books) in one single book.



Tuesday, July 09, 2024

New version of the Chess Gambiteer (training) software.

In recent month,  updated the awesome Chess Gambiteer (open source) package (and gambits
in the polyglot book) again.  You can get this free chess training software at:

Chess Gambiteer

(being open source, it's completely free (suitable for chess training).

Ofcourse you also can buy the GM Alterman video series:

GM Alterman gambit videos

but playing around with with the Chess Gambiteer package (play against an engine where
you can set the strength in Elo) or watch mastergames  with gambits, based on Winboard 
and without one combined GUI but simple double clicking on the .bat files should be easy
enough (for most users, and then there is a readme.txt as well ofcourse).

As GM Alterman states (in his book with White gambits), players at lower levels (than GM)
learnmuch more from playing gambits, especially tactics (but also attacking plans) than
simply parroting positional GM games (eg. Ruy Lopez, or Slav). In the old days of
chess it was thought by many players (including Gm's) that you can build up  a positional
advantage with White, if you choose the 'best' opening moves. This turns out to be not 100 pct
solid, if Black defends well, also knowing such lines, you can't get a fundamental advantage 
in the game (for top engines at longer time controls the end result is draw).

Thus playing sharp (often gambit) lines, especially those you know, is a better way to
induce tactical opportunities or exploit possible tacticial mistakes of your opponent in the
game; whereby in blitz it often doesn't matter how sound the gambit is (in the above Chess
Gambiteer package, the gambits in the big book are quite sound, and in the small
(Polyglot) opening book, reasonable sound. And when playing against a weakened engine,
which plays such sound gambits, you first learn defensive skills and then also by learning
those gambits for yourself, you can also practice those gambits against the comp (or online
opponents eg. on chess.com or lichess.org).
Good luck!

Nb in recent two months updated the content of some gambits in my educational book about
chess openings (link below), especially the Smith-Morra. Compared to known theory (and
historical games). It should be now again a higher quality, of importance for those
intermediate players who may choose to play gambits e.g. in blitz or rapid.
Edition 2.04 (July, 2024):

    Kindle version of the book

In general, talking about modernized opening theory (as result of the Nnue engines), besides some recent opening books with 'Modernized' or 'Revisited'  in the title as from Thinkers Publishing in Belgium, i don't know of any other chess opening books which is dealing simultaneously with all new theory at once (which i've done by chosing an optimal repertoire,  at two levels, intermediate or advanced).  You can buy Chessbase 17 ofcourse, for 190 $ or so, but for intermediate players this book (with lots of diagrams) should give sufficient info for opening study at such levels. And it's a lot cheaper too :)

Monday, April 22, 2024

New Edition (opening book)

 The new edition of my chess opening book has arrived!

End December a new version was ready, with everything corrected
according to the new neural net (NNUE) evaluations, and layout
changed/updated (less info for beginners, and the former intermediate
chapter(s) now changed to 'advanced'.

The new intermediate chapters (the former chapter with 1.e4 for 'beginners')
after the updates, now are called the chapters for intermediate players,
more in line with the educational guidelines e.g the Dutch step method
(with mostly only general openig guidelines at the beginners phase).

Although the basic repertoire did not have to be changed,
many moves in variations >5 or 6 ply or so had to be updated.

March 2024: final corrections to the book, the result now
is a high quality, solid opening/repertoire book for all levels of play
(up to IM level or so). 

Ofcourse it's a matter of taste at the advanced levels, what variations
you want to choose for your repertoire, but at least the lines given
in this book are solid, and give high practical chances for achieving
an opening advantage during the opening (if your opponent deviates
from the recommended lines).

E- book available at Amazon Kindle:

Kindle version


Thursday, September 21, 2023

New edition of the opening book coming soon

 Next months i am going to  work on the new edition, which will probably take me a few hundred 

hours.  At first, the main updates will be presented in the E-book versions, eg on Amazon

Learning-Chess-Openings-intermediate-levels-ebook (Amazon)

The paper version will get the same updates, but in addition also the comprehensive

appendix with the details of all variations (not in the E-book) will be updated, thus 

making it a timeless reference guide for almost all chess players.  

Note basically, more advanced players will notice it is a 'repertoire' book; because

chess fundamentally is a draw, it is possible the chess players is deviating with his/her

'repertoire'' (built up after beginner level) from the variations in the book(s); however

in some situation we already indicate where such deviations are possible (eg for

more adventurous players,  or sometimes for more advanced players), and in any case

the repertoire given in the new edition of the book will be perfect rocksolid, timeless

and suitable from a practical point of view for the majority of chess players.



Improving opening theory (update of my chess book)

 A few years ago i wrote a book about opening theory specifically aimed

at beginner and intermediate levels; this is/was the paper version of the book:

Better-Chess-Openings (Amazon)

There also is an E-book version (and some other review) with various outlets (eg lulu.com/kobo), but the above  is key. The book was based on chess programs (engines) at that time, which already analyzed positions better  than  human chess grandmasters. However in recent years the chess engines were again considerably improved  due to the use of neural networks (the NNUE approach). As a result I had to check the content  of the book, and the recommended 'repertoire' (main  variations for Black and White). For this purpose in  last two  months I have analyzed two million of the most important opening positions added  the improved results to my computer chess 'opening book' did 'backsolving' some checks and finetuning on the final results. 

Luckily I found that  the  older 'main' opening choices ('repertoire')  still basically are correct (as result  of earlier deep/thorough analysis it appears I  was  ahead of my time) but many variations now do need an update in specific  moves,  and  sometimes  the order  of importance  for specific variations (recommended top choices) will be  changed.  This means it now is time for a  second, completely NEW, improved Edition, based on the latest  ('NNUE')  engines and a systematic analysis of  ALL relevant opening positions starting from scratch. 

Thereby many variations will get an update wrt the specific moves usually from move 3 or 4 onwards, and sometimes  the order of importance for specific variations (recommended top choices) will be changed. An example of a variation  which  has become almost obsolete as result of the engine analysis , is the French Winawer for Black. While I already  not recommended it for Black, I know can list the best moves for White to refute the variation,  in case  Black would play such the -erroneous/outdated- ...Bb4?!.  Also in the chapter with gambits,  and the more advanced 'positional' chapter (with 1.d4) there will be changes in the recommended moves, usually after move 3 or 4 or so, while maintaining the main structure  of the (sub)chapters. 


Chess is solved (2025)

 Chess is 'solved' and it's a draw. As in shown/discussed in my recent article on academia.edu: An ('ultraweak') solutio...