As I'm re-watching TOS, I notice 2 cases within the first few episodes where Kirk defeats Spock in chess. At least 1 of the 2 times, if not both, Spock failed to see a checkmate that was only 1 move away.

I'm surprised about this as both a Star Trek fan and as a FIDE Arena Master (and chess coach). Vulcans are supposed to be highly logical with disciplined intelligence and concentration.

As Spock noted, chess is essentially math. That's why even low-end computers running a chess engine can beat the best players in the world. It seems like Spock blamed it on Kirk's

"illogical approach to chess"

I fail to see how that explains Spock's inability to spot a potential checkmate that's only 1 move away. That would be a beginner mistake even for a human.

Is it that Spock lacked the strong logical prowess we normally associate with Vulcans due to his mixed heritage (being part human)?

  • 17
    "Let the captain win?" Commented Nov 26, 2020 at 20:55
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    Because 4D chess is less about logical positional play and more about emotions, apparently. Hence why Troi can beat Data at it.
    – Valorum
    Commented Nov 26, 2020 at 20:59
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    I don't have a decent answer for why Spock couldn't see that a potential checkmate was literally just one move away. But it might entertain you to read a licensed Star Trek novel from the 1980s: My Enemy, My Ally by Diane Duane. Early on, James Kirk is the viewpoint character playing an experimental new game -- 4-D chess, instead of that boring old 3-D stuff -- against Spock, and Kirk ruefully admits to himself that the strategies he'd spent years developing (for taking Spock on in 3-D chess), which had finally begun to work for him, were now turning out to be useless under the new rules.
    – Lorendiac
    Commented Nov 26, 2020 at 21:12
  • 8
    I always thought this was because the script writers and producers had no real understanding of chess themselves. The show was written long before Kasparov lost against Deep Blue. At the time computers could still be beaten by human grandmasters, and people tended to be quite fond of the thought that humans were inherently superior to computers because they'd have some kind of intuition or other inexplicable capability a machine would never be able to possess.
    – Lykanion
    Commented Nov 27, 2020 at 10:07
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    According to Memory Alpha (and also my own memory), TOS episodes showed 3D chess, not 4D chess: memory-alpha.fandom.com/wiki/Three-dimensional_chess. Or am I missing something?
    – dennis_vok
    Commented May 19, 2021 at 6:47

7 Answers 7


Canonically we do not have an answer to this.

In universe though Vulcans are logical but they are still biological, a computer can calculate and keep track of all possible moves a biological brain has to pick and choose what it thinks the most likely moves are and plan its own moves in accordance.

Or alternatively Spock was not actually paying attention to the game after all it would not be logical to devote ones full attention to a past time if there was something more important to think about. This is probably more likely if Spock actually did not see a checkmate in 1 move.


We can also look to Troi beating Data at 3D chess: (note: 3D, not 4D)

(a 3D chess game is in progress)
DATA: The characteristic response to the Kriskov Gambit is to counter with the el-Mitra Exchange, particularly since I have already taken both your rooks. By missing that opportunity, you have left your king vulnerable.

TROI: We'll see.

DATA: As you wish, Counsellor. Check.

(Troi makes her move)
DATA: Intriguing. You have devised a completely unanticipated response to a classic attack. You will checkmate my king in seven moves.

TROI: Data, chess isn't just a game of ploys and gambits. It's a game of intuition.

DATA: You are a challenging opponent, Counsellor.

If Troi can beat Data (who is likely arguably an even better strategist / calculator than Spock), Kirk, who Spock says used similar unexpected tactics and unpredictable reactions, also stands a good chance.

Also - in the game we see Kirk and Spock playing - Kirk is very much aware of Spock's half-human side and is goading him, which could cause Spock to make a blunder:

KIRK: Certain you don't know what irritation is?

SPOCK: The fact that one of my ancestors married a human female

KIRK: Terrible having bad blood like that.

(later, to Mitchell)

SPOCK: He played most illogically. His next move should have been the rook.

Spock's response to Gary Mitchell as to the chess game clearly shows that Kirk, like Troi, played illogically, which created the win condition. Spock's insistence that Kirk should have played a particular move, indicates a bit of unwillingness to adapt to simply 'play the board' as Jeremy Silman (chess player / author) suggests.

(Similar to Data vs Kolrami in a game of Strategma, where Data plays not to win, but simply not to lose, which is an unexpected and maddening tactic to his opponent)





In the book Star Trek - Enterprise: The First Adventure, while Spock was practicing a solo game Kirk spots a mate in 3 that he couldn't see. Spock says it was illogical because Kirk risked his queen and knights, perhaps suggesting that risk is illogical. So they then played a full game together. Spock notes in his log that;

...at first I easily compelled him to play on the defensive. His radical solution to the problem I had set was, I decided, a fortuitous random move. Certainly his strategy and tactics did not appear particularly far-sighted. On this basis, I gave up my premature assumption that the Enterprise had gained a chess expert as well as a Captain. Then however, Captain Kirk executed a flamboyant one might even say reckless series of moves. He took the game. It was a most instructive experience, one worth repeating.

Perhaps worth mentioning, there's another incident in a episode of the Star Trek cartoon series where Spock's over-reliance on logic prevents him from properly assessing the illogical nature and irrational response of an inferior alien caveman-like race when presented with a superior force.

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    Hi, welcome to the site. You could improve this answer by editing it to include the name of the specific episode of the animated series that you alluded to here. Commented Jun 29, 2023 at 10:00

Star Trek has a running theme of the human vs the logical with Dr. McCoy often berating Spock for lacking emotion, especially in the final scenes.

Here, I take it that the writers are simply showing that being human is no barrier to defeating a logician in a game where one might think logic would help.

(In one sense, chess is already 4d as one requires the dimension of time to play!)


We don't have much evidence about how often Kirk wins. In the two games shown on screen, one ends before the game is resolved, and Spock loses the other (with extenuating circumstances).

In "Where No Man Has Gone Before" Spock says he is one move from checkmating Kirk, but Kirk finds a response that does not immediately led to him losing (the game is then interrupted so we don't see whether Spock or Kirk would have eventually won the game). This is possibly an embarrassing mistake on Spock's part, but it could be interpreted as a simple fact equivalent to Spock saying "There is a possible next move for me that wins the game," and Kirk then making a move that eliminates that possibility.

In "Charlie X" Spock loses unexpectedly (as you say, not even aware that he is in danger of checkmate). In this case, however, Spock is distracted - just before the checkmate, Spock is perturbed by Charlie's mysterious knowledge of the fate of the Antares before the Enterprise's sensors detected a problem ("He seemed to know what happened to the Antares before we did."). Spock is not entirely emotionless, no matter what he says, and a possible danger to the ship is more important than chess.

The other episodes that feature 3-D chess don't feature Kirk and Spock playing each other (unless I'm missing one).


I thought it was a situation of Kirk cheated at the game making an invalid or as Spock put it an illogical move but knew well enough that pointing out that Kirk is cheating won’t effect anything. Spock is stuck in the situation of we both know that I won the match but he will never get Kirk to admit it.

  • 7
    Can you offer any evidence to back up this very bold statement?
    – Valorum
    Commented May 18, 2021 at 14:33
  • 2
    @Valorum - "I don't like to lose" - Admiral James T. Kirk ;D
    – NKCampbell
    Commented May 18, 2021 at 16:21
  • ha! OK, that one is more of a TV conspiracy theory, but makes some sense.
    – Hack-R
    Commented Jun 29, 2023 at 22:36

The chess scene was all about developing the characters of Kirk and Spock, as well as their relationship. The point of the scene was to draw Spock as logical, pragmatic, careful, and methodical, contrasting with Kirk who is intuitive and bold, perhaps to extreme. In the chess scenario, Kirk takes risks which Spock would deem foolhardy and so dismisses them; in so doing, he leaves himself unprepared for the sequence of moves which ultimately leaves Kirk in the winning position. This foreshadows their responses (Kirk's in particular) to the events which unfold later. Kirk wins out by doing the one thing his adversary fails to anticipate - usually something extremely risky.

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