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Schrödinger's Chess Puzzle

  • NM GargleBlaster
  • | Mar 29, 2014

Warning - the article you are about to read might produce a variety of symptoms, including lightheadedness, altered vision, eye or face twitching, jerking or shaking of arms or legs, disorientation, confusion, or momentary loss of awareness. 


Hello, chess.com readers, and allow me to present a brief backstory about the the puzzle I am about to present to you.  It dates from the time of ancient Egypt under the rule of King Ramenhotep the Second and his most holy cat, Pickles the Seventh.  Pickles was fond of chess and one day chased a stray rook into the catacombs underneath Ramenhotep's greatest Pyramid, the Qualcomm Discount Slave Emporium, and became trapped within an area still under contruction.  Ramenhotep, upon learning of this calamity, summoned his wise men, viziers, and short-term prophets in an effort to determine if Pickles was still alive.  Alas, the King's advisors could not agree upon his cat's existential state, and to make matters worse his construction crew had in the meantime gone ahead and sealed off the entire section and was now hard at work with plans for a second food court and ice rink.

"What does this have to do with chess?", I hear you ask.  Well, I'll tell you, oh impatient reader.  Apparently the mystic energies produced from Ramenhotep's most psychic assistants, combined with Pickles and several chess pieces, mixed together into a brew of quantum chess/cat probaballistics too potent to be contained within the bowels of the Emporium.  Fearing the worst, Ramenhotep declared a general evacuation of the entire area and from a great distance witnessed his greatest Pyramid explode and, from its ashes, two creatures emerged - a Quantum Phoenix, the rarest and most confusing of all birds, and Pickles the Eighth, in hot pursuit.  Evading Pickles' grasp, the Phoenix flew to Ramenhotep, and spoke thus:

"Hello.  My name is Fnord.  Fnord the Phoenix.  Your recent quantum mishap has summoned me from my native plane of existence which is actually quite nice this time of year, so I'll be brief.  I bring you a puzzle, oh King, for you to solve - if you cannot, your empire will crumble and your slaves will flee and eventually become pretty good at chess and violin playing.  Good luck."

Here is Fnord's puzzle.


And now, the question that Ramenhotep could not answer due to Rybka being 3000 years away... is this a draw? With zero pawns on the board, Black's two knights cannot mate, but with one blocked pawn it is sometimes possible. However, here we have no less than four pawns for Black to deal with. Is this an advantage or a disadvantage? For thousands of years this position has remained unsolved and I call upon the sages of chess.com to once and for all put Ramenhotep's troubled spirit at ease. What sayeth thou? :) 


  • 15 months ago


    I didn't know that black could mate with a blocked white pawn, but Nd5 still draws. The line given is black's best attempt to win, but an easy draw.

    The a-pawn and pressure on the c-pawn secure a draw.

  • 16 months ago

    IM Runner

    I referred to the moment from which black takes already the pawn d7, leaving pawn c4 the only one left.

    About a4 instead of e4 (e4 was my own suggestion in order to check the Straigthforward way), i don't know surely about it. The problem with that is, i don't trust the engines regarding that (except white wins a knight within 20 moves, which is not realistic); whereas there are to many pieces for the endgame-databases...

    But nethertheless, i think you should keep the 50 moves rule. Things like that are pure rarity, whereas often there occurs R+B vs R, which is drawn, but the stronger side often tries (succesfully); it is much more important to keep the 50 moves rule for that cases

  • 16 months ago

    IM Runner

    Indeed, i checked it again (also without e4-e5 since it just gives away 3 moves)-
    How i mentioned earlier, white draws, except the white king will be placed at the wrong corner. Well actually, with your sequence, balck can force the white king exactly on the right places to mate under 50 moves.

    You can actually see, the evaluation jumping from mate in 40 to mate in 70, just if black doesn't play the exact right first 5 moves!

    So after spending a long time with this problem, aswell with some help the audition, I can guarantee the statement:

    "This 2-knights endgame is won for black, UNLESS! 1.e4 is the wrong strategy (to push the pawns as far as possible) and instead go for 1.a4,Ka2 and push the a-pawn in hope to exchange it for a knight; all this while the blacks king is to far away"

    Unfortunatly i don't have the time to check the last sequence; on idea is aswell (if black plays Ke3-e4-d4-c6...) to push THEN the e-pawn. Destract the king with the a-pawn, the knight c4 with the e-pawn und to push c4 to get finally the drawing-last-pawn-on-c4 position with the king near enough to d4 to hold on by the 50-moves-rule

    Good luck analysing?! Laughing

  • 16 months ago

    IM Runner

    DM_Knight: see my sequence last page;
    if (as it seems) it is enough to push the white pawn on c4 to hold (that means if black doesn't block it with Nc4 at the end) all white has to do is to attack the black's knight with his king,

    e.g. in your sequence 18. a5 Kd5 (if Nxa5- 19.c4! draw) 19.a6 Kc6 20.Ka2 Kb6 21.Kb3 and c4 soon with the seemingly draw i mentioned.

    With the pawn on c4 instead of c3 it takes a lot longer for black to mate

  • 19 months ago

    IM Runner

    @ sogcelak: I checked the position with the pawn on c5 with tablebase (nalimov). He says it's mate in 60 and if you choose as a human the 2nd line, which mates one move earlier but don't push the pawn to early, then it will be mate in 58 without any pawn moving.

    Sorry, but Nalimov can't find a win within 50 moves for black and it also doesn't  count the 50-move rule

  • 19 months ago

    IM Runner

    it's helpful to look in the last pages for ideas-

    As far as I analysed even 14.Nxc4 draws, if black isn't able to mate without taking white pawns. If not, then white is able to remai with the pawn c5, which is losing, but after 60 moves, that means this would be drawn.

    See yourself

  • 19 months ago


    If the Rook is taken then the game is an immediate draw by stalemate. White cannot make a legal move and yet is not in check. Therefore Black will not take the Rook and will try and convert his huge material advantage in another way.

  • 19 months ago


  • 19 months ago


    I don't really understand this, maybe is part of the story or something? Why the rook is not taken?

  • 19 months ago

    NM GargleBlaster

    Oh, OK.  Sorry to have underestimated your computer. :)

    What about with White playing 14.Nd5 in place of 14.Nxc4?

  • 19 months ago


    The d8 knight can't move to far, or else the d-pawn will queen. If black attacks, it must be quick and decisive, or else white queens. Unfortunately, the pawns are placed in such a way that it's really hard to get to the king in time.

  • 19 months ago

    NM GargleBlaster

    Kylos, yes, I was wondering about that, actually.  Still pretty murky, but looking drawish.  Maybe. :)

    Also, for sogcelak: the computers will often say that White is "losing", but the lines they give are sometimes longer than the normally required 50 moves without a capture or pawn move.  Thus the paradox (of sorts).

  • 19 months ago


    Schrödinger's cat, anyone?

    Famous quantum physics experiment! Smile

  • 19 months ago


    too easy..

  • 19 months ago


    a lowly slave heads for the promise land... really?

  • 19 months ago


    nice puzzle

  • 19 months ago

    NM GargleBlaster

    Perhaps I wasn't sufficiently clear.  The question is whether Black can win, not White.

  • 19 months ago


    Good puzzle

  • 19 months ago


    The White Rook is not taken because it will be a STEALMATE.

  • 19 months ago


    Interesting position..

    I checked the final position with houdini 4. And it sees mate in 94 (Depth 30). Starting with 1.Nc6! a3 (the best choice) 2.Ke3 Ka2 (and when I started making the moves on the board the engine sees a mate faster and faster) 3. Kxe4 a4 4.Kd5 Kb1 5.Kd6 Kc2 6.Kxd7 Mate in 44 (Withing the 50 moves)

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