# Is chess a game of skill or chance? To what extent?

I want to know whether chess is a game of skill or game of chance, and how much is the degree of skill or chance in terms of percentage.

Edit (21 Feb 2014):

Please make sure that your answer includes credible references. To be sure that chess is a game of skill (or chance?).

• no chance at all, if the player is good, he makes no mistakes, if not he makes blunders Feb 17 '14 at 19:22
• Comment on update: Courts adjuciate and settle legal disputes, but when we discuss scientific or philosophical questions, court decisions can largely be ignored. Feb 18 '14 at 15:39
• @RauanSagit any court of any country, no I am not kidding. can you explain throw a little light on you what you said - " which should be well defined in the question body text in the first place. Otherwise, answers will start becoming subjective " Feb 20 '14 at 14:12
• What I meant is that the word "chance" has to be well defined in this context. Otherwise, the answers will differ because the underlying definition will differ. If chance is the probability of not making the best move, then chess has plenty of chance. If chance is the probability of a Bishop moving although you are moving a pawn with your hand, then chess has none of it. Cheers. Feb 20 '14 at 14:25
• @RauanSagit I want to contact you via email and learn some chess, you seem to be a master, how can I get in touch with you ? Feb 20 '14 at 14:30

If we remove the component of flawed, human players from the equation and consider just the game of chess itself as it is spelled out by the rules, then chess is purely a game of skill with no room for chance. That is, it is in principle possible for there to be a perfect chess player that plays optimally against every possible move sequence by an opponent, and that perfect player would never falter due to chance or luck. Such perfect players already exist at the level of chess positions with only a handful of pieces: endgame tablebases consist of all the information necessary for perfect play in those positions, and if you play from such a position against an opponent with access to those tablebases, chance can play no role in stopping them from getting their deserved result.

However, the problem of computing a tablebase for the starting position of chess, with its 32 pieces, is far, far from tractable. So while optimal play does exist for all positions in chess, nobody knows for sure what optimal play is for the vast, vast majority of positions. Looked at in that light, when two humans (or even strong chess engines) play a game against one another, something that can reasonably be viewed as chance (for one side at least) can definitely play a role, but for what I have in mind at least, the root cause of any outcome is still skill (or its temporary absence).

Here's an example of what I mean. In the recent Zurich Chess Challenge, Nakamura was playing a fine game against Carlsen, to the point where he had an overwhelming, winning advantage. At that point, it could safely be said that Carlsen "deserved" to lose.

``````[fen "4r1k1/1p3pPp/6q1/2pPpNP1/p1n1P3/P6Q/7R/K7 w KQkq - 0 1"]
[White "Nakamura, Hikaru"]
[Black "Carlsen, Magnus"]
[Event "Zurich Chess Challenge"]
[Result "0-1"]

1.d6? (1.Qf1!)
``````

But Nakamura made a crucial mistake that let Carlsen off the hook, later followed by further poor play that even allowed Carlsen to win. If someone were to say, "Carlsen was lucky to win that day," I'd say there's truth to that. (Carlsen certainly deserves credit for defending in such a way that Nakamura could still go wrong, but even so, he was fortunate that Nakamura erred as he did.) But the luck from Carlsen's side originated from nothing more than a momentary lack of skill on Nakamura's part. Finding the right move was entirely within Nakamura's power, but he wasn't quite skillful enough to find it in that moment.

As in most human endeavors, there is some element of chance in the competitive results of chess games. But that luck for one side generally comes in the form of what kind of lack of skill one's opponent shows (and when).

• Thanks... Well can you give references where I can find all about it. Feb 16 '14 at 22:42
• @258135, I'm not sure what you want a reference about, exactly, but maybe this will point in the right direction. Chess is an example of a game of perfect information (see e.g. en.wikipedia.org/wiki/Perfect_information), as opposed to games like poker where, though skill is certainly involved, the lack of information about what is in other players' hands leads directly to players having to make decisions influenced by probabilistic considerations (in a way that isn't present in chess). In chess both players have the same info, but some players can do more with that info than others.
– ETD
Feb 16 '14 at 23:34
• I've heard some game theorists argue the opposite, that with perfect information there is no skill involved. Feb 16 '14 at 23:44
• Yeah, in chess there is a simple strategy: just play optimal moves! :) Feb 17 '14 at 0:28
• +100 I agree that to an observer a mistake can seem due to chance. Yet the root cause is a skill (or lack of skill) of the player. In chess, there is a 100% known information for both players. Yet, it is so big and the actual "path surface" of a position is hidden under layers of moves. Thus, it is hard to "see" forward and choose correctly. Yet, the quality of your decision (move) is your skill. "Guessing well" is also a skill...? Cheers. Feb 27 '14 at 16:22

By the commonly accepted definition of "game of skill", chess is 100% a game of skill. It has no random element at all and both players have full information about the game state at all times. Players do say things like "I was lucky that my opponent blundered", but that's not what is generally meant when people talk about "games of chance".

• +1, but re "no random element at all": isn't there randomness in the choice of which side of the table you're on? Feb 17 '14 at 18:53
• If you want to consider color determination as part of the game of chess, I won't stop you.
– dfan
Feb 18 '14 at 1:27

As a game of chess progresses from one of incomprehensibly vast complexity (with a great many useful moves open to many pieces) to manageable complexity (with fewer useful moves), play transitions from (hopefully) skillful (conscious or subconscious/intuitive) applications of

1. heuristics, probabilities, and targeted but incomplete analysis (often small differential analysis from remembered/studied games), to

2. exhaustive analysis of the relevant paths the game may still take (again, often differential analysis from reference games).

The players themselves - and human observers - may not be able to reliably identify this transition, as they'll be prone to feel like they're in stage 2 a little early - while there are still one or more potential plays that could upset their plans. And a careless move may transition a player back to stage 1.

There's definitely skill involved in both stages: in as much as skill is "the ability to do something well; expertise" (OED) - and many reasonable criteria for "doing [chess] well" are possible, such as say:

• one's ability to find "better" or avoid subtly "worse" moves, whether in stage "1" or "2" above, and where

• "better" and "worse" are evaluated by the impact those moves have on the outcomes of games they and/or other players have after those moves, all compared to others in the chess-playing community.

(I phrase it in terms of individual moves and not "wins"/"loses averted" because in any activity someone may have skill but not consistency; they may not be a great competitor e.g. if they're feeble of concentration, flustered by pressure, unable or even uninterested in manifesting their ability consistently in competitive settings; they might just like analysing complex end games for example, but be very good at it...).

In stage 1, there's also an element of luck: there's at least the potential for:

• some reasonable-seeming move to turn out poorly (which would be unusual and therefore reasonably deemed "unlucky" if the heuristics and partial reasoning were overwhelmingly sound and skillfully applied - i.e. of a high standard compared to the chess community overall), or

• a great opportunity that wasn't deliberately set up to become available, or

• a relatively careless move to have consequences that weren't foreseen, which might work out very well or very poorly.

But, if one player has a lot more skill than the other player, the frequency and severity of significantly "unlucky" moves they might make, or "lucky" moves their opponent might make that they hadn't foreseen and protected against, decreases, until it becomes astronomically unlikely for enough consecutive "(un)lucky events" to have more bearing on the outcome of the game than the skill differential does.

On the other hand, the closer the skill level the more likely that "luck" will be the deciding factor. Here, "luck" might be occasioned by conscious awareness that a choice between moves is being made arbitrarily, or it could be an intuition/hunch to choose between moves that in this case isn't actually usefully informed by any experience or subconscious analysis. There's even a degree of luck in whether a player making an arbitrary choice between what might in some absolute sense be equally good moves happens to choose a move leading to a situation their opponent is more or less skillful at handling (e.g. because their experience and study is more relevant to one position than another).

You could compare this tide-of-skill versus spontaneous-fluke factor to say tennis: a lucky outcome could see me win a point against Roger Federer - perhaps by playing a very low percentage but skillful shot that happens to work out that one time, or even by having a shot hit the net-cord and drop over, come off my racquet frame at an unlikely but advantageous angle, or bounce strangely for Roger. But, the chance I'd win an entire game is maybe 0.1% (?), a set would be like winning lotto twice in a row, and a match - well, the universe might end first. (Sane caveats re Roger being mentally/physically fine etc..)

The more a game requires a great many moves to shape and turn the outcome, and the lower the chance for a fluke beyond either players' control, the more predictable the outcomes are, and the more the skill differential ensures the outcome, even if that skill is probabilistic and not deterministic. Skill is a huge factor in chess, but skill is not a constant for a player - they may be more skillful at handling play from certain positions than others (perhaps they just read a book on a relevant tactic), and occasionally a player of lower average skill might prevail based on some particularly relevant but limited skill (and be deemed lucky that play led to a situation where they could apply it). In close matches, and perhaps in beginner's matches where more of the movements are made arbitrarily without even a guiding strategy or heuristic used, luck starts to play a significant role.

I think it's interesting to compare this to baseball, I read a book about it years ago that explained how some Wall Street quant types crunched the maths and found that the worst team in the top league had something like half the chance of being the champions that the best team had... i.e. surprisingly little impact on odds came from achievable differences in skill (given the top team had vastly more budget to hire players considered "stars"). For example, while the percentage of swings that made contact varied with batter, the out/1st-base/2nd-base/3rd-base/home outcomes were in similar proportions: you might observe that it took skill to hit the ball more often, but doing so was so difficult and the angle of contact so uncontrollable that what happened when you did basically came down to luck. Overall, luck could easily swing a game.

Separately, and this may be controversial and I'm not claiming it's true - just reasoning about the implications if it happens to be true: I saw a study report that when chess grandmasters played good club players, starting at random board positions that would not occur during actual games: the grandmasters lost their main advantage as they didn't have a huge wealth of applicable reference games with which to compare; reduced to actual logical reasoning without any particular advantage - they only had a smidge more than 50/50 chance of a win. Does that mean chess is less about skill than my above assertions imply? Is a vast memory of games itself a skill? I'd say so - it clearly allows you to "do well" in non-random games, and that's all the OED requires. Further, consider say a language translator - we'd consider the size of their vocabulary to be an aspect of their skill level.

• Do you have a reference to the study you mention in the last paragraph? I know that studies have been done showing that masters don't memorize random board positions better than lesser players do, but hadn't encountered studies about actual play. Given GMs' great advantage in calculation I'm surprised they didn't perform better.
– dfan
Feb 18 '14 at 15:51
• @dfan: I'm afraid not - many years ago, but I suspect it was online. I doubt I'd remember it if the results hadn't been surprising. For that matter, I doubt I'd have seen it as the media probably would not have reported it widely - selection bias! O_o If I stumble upon it with some Google foo will let you know, but no luck from a quick attempt. Feb 19 '14 at 1:30
• I am suspicious about that last paragraph, I am sure I would lose 99.99999999% of the time against a GM on a Fischer Random game. Feb 21 '14 at 18:20

White always starts with a slight advantage by having the first move. So if your colour is decided by flipping a coin or whatever, then that's an element of chance!

But it has been accepted that the game itself is 100% skill.

• Wrong. Most people think that White starts with a slight advantage. However, that hasn't been proven yet. It could be the case that perfect play on both sides would result in a draw or even Black winning. Aug 19 '17 at 23:19

I would submit that there is an element of luck in chess. For eg., imagine a game between two players of roughly equal ability. Suppose the position becomes a very open tactical position with possibilities for both sides. In such a situation a lot of tactics are possible. As human beings, we may not be able to calculate all the variations in such a position. So in such a situation, we would normally choose a particular tactic based on gut feeling. It may well turn out that the tactic chosen is the best one which may result in a winning advantage. However, given the open nature of the position, it may also turn out that the tactic chosen is not a great one and that the opponent finds a good refutation for that particular tactic. So there appears to be an element of luck in deciding which tactic to choose in a position which offers many possibilities.

• +1, I was hoping to see an answer like this. In fact I was very excited as I thought for a moment that the top answer was based on this argument. I always like to illustrate this using an extreme example. Suppose I take 50 years of my life to write down a sequence of stripes on an endless scroll of paper. Then, I give you 2 hours to figure out whether I wrote an even number of stripes, or an odd number. People would say that "in theory" you can win the game, but humans just can't count fast enough. "In practise", you have to be lucky. Mar 10 '14 at 20:14

As chess isn't completly solved, nobody can guarantee that `1.a4` doesn't force a win. However people don't play perfectly (there is room for error), so people will try to use familiar paths to increase his chances of winning. With trial and error they know what is more likely to work and than not.

A cat (by luck) can beat us in chess by slamming his paws (very unlikely, but it remains possible). But why is a GrandMaster more likely to win than a cat?:

Grand Masters are very skilled in picking the moves that have more chances of winning.

The question "is chess a game of skill or chance?" can be reworded to "will a cat win more than about 50% of the time in chess or not?". And then the answer is obviously clear, chess is a game of skill.

But, is there some luck involved? Yes, a cat can beat us by chance.

To how much extent is chance involved? Here is the hard question, as long as players don't calculate 100% of the possible replays and future moves, they are trying to guess which move will perform best, they can rarely calculate everything (only possible in the late game or forced moves by check on the early/mid game). My guess would be that they can't calculate everything 98% of the time, maybe 95% without time limits like correspondence chess.

Chess is definitely a game of skill and not by chance. One of the greatest chess players ever was the American Robert James "Bobby" Fischer. He acquired the skill by training everyday. He brought a chess board with him wherever he went, even while taking a bath.

It will take you more or less 10 years of real training to become a Grand Master or, at most, a world champion.

I am just barely 2200 FIDE rated but I can say skill is 95% and the rest is where the luck goes.

I'm pretty sure that by formal definition, chess is a game of 100% skill and 0% luck. Why? There is no "outside element of randomness" that could influence the outcome of a match but cannot be directly controlled by at least one of the players.

In other games, the order of cards and the outcome of the roll of a die cannot be influenced by players... at least not if they play by the rules and do not use some mechanism of cheating :)

The inherent "human factor" is not considered "chance". I.e. if player B makes a mistake that lets player A win, we don't say player A was lucky, we say he played a better game because B made a mistake and A didn't. Of course players can introduce an element of chance/randomness by making random moves. If a position is too complex for a player to understand, he could mentally or actually flip a coin to decide which move to make. Or he could pick the best move for completely wrong reasons. This sort of "chance" is part of every game, so if you want, consider it 1-5% chance. More for beginners, less for skilled people because skilled people will not need this type of "guessing".

Another thing to consider: A good player will not lose a single game against a weak player. I don't think the same will be true for poker or other games involving chance so this also shows that it's a game of high skill and little chance...

In theory, chess is 100% game of skill. But since chess is unsolved in practice, is it purely a game of skill?

As of today, if a human/computer analyse to some depth `D` and result in `N` board positions with same evaluation `E`, then the final choice could be purely random.

Therefore until chess is solved, with limited computing power, there is a small component of chance.

Edit: Consider 2 computers playing against each other. Lets say, in theory, we know that `1.e4` wins, `1.d4` loses. But the computers have limited power and evaluate both `1.e4` and `1.d4` as same. The computer randomly breaks the tie - winning or losing by chance.

Edit 2: How much of it is chance? IMO the chance component depends on the evaluation depth. For 2 computers that can analyse only upto a depth of 1 - the chance component is high.

Edit 3: Definition of chance: An external source of randomness which is not known to either playing agents. 2 computers playing each other can produce different result.

• The thing is, what you're describing is not a game of chance. There is no random factor that plays into it in the game rules. In other words, if you go through the play, you know where you've made a mistake. The fact that your opponent is also a thinking being (be it human or computer) is not a factor of chance in the game - it simply means that he has different solving algorithms, optimal or not. The randomness is on part of the players, not the game itself. If you count player randomness, all games with a player are games of chance. Which means the distinction would be completely useless :) Feb 17 '14 at 10:03
• game rules do not have chance component - therefore in theory chess is game of skill. But 2 computers (with fixed h/w and algorithm) can result in random outcomes. Which is not true for a solved game of tic-tac-toe. Feb 18 '14 at 3:27
• I am not sure if "solved" is related to "chance". Feb 18 '14 at 10:48
• it is related - see my edit. Feb 19 '14 at 16:14
• The "decision making process" is a different topic. Chess is a Perfect Information (en.wikipedia.org/wiki/Perfect_information) game. Again, it depends on how "chance" is defined, which should be well defined in the question body text in the first place. Otherwise, answers will start becoming subjective. Cheers. Feb 20 '14 at 13:17

No, chess requires 100% skill, that's why bookmakers may offer poker games, dominos etc., but absolutely not chess because a good player will constantly win.

Chess is about using your resources in a clever way. As a human body, you have limited resources and planning is needed. A game at classical time controls can take up to 6 hours and being focused for 6 hours is simply impossible. It is hard to eliminate the factor of "human error", "blunder", "being too hasty" and the very important "time trouble" frequently seen on all levels. Yet, it is possible to minimize these problems and thereby improve your results.

I think that chess is all about skill and what some refer to as "chance" or "luck" is the human factor mixed with the simple fact that some positions are a hard nut to crack! For example, you can calculate all the lines correctly, yet have trouble to evaluate the final positions. Alternatively, you may think your calculations are correct yet miss a devastating in-between move.

On average, skill will decide your results. Yet you need skills in several areas, not just e.g. calculation. Thus, some players miss out on one or more areas and start attributing those to "chance" or other factors. For example, if you blunder in your own time trouble, obviously you lack one or more skills. You cannot attribute this to your opponent being lucky. All in all, your skills will maximize your chances of winning, as an individual. The game itself has a certain degree of uncertainty due to several factors. You can choose to call it "chance". You can also choose to call it the "dynamics and uncertainty of a chess game".

I think Chess becomes purely a game of skill only at the Grand Master level where the element of randomness is nil, where strategy, tactics and deep calculations define the game. Chess at Grand Master level is purely Math. But down the hierarchy, skill and chance both become a part of the game.

In fact, if a player has studied his opponent's weaknesses, he might want to take a few chances rather than opting for the time tested standard moves. At amateur levels, players often deviate from the standard course of the game, even just for the fun of it, and willingly take chances.

'Chance' does have the connotation of lack of skill or lack of deep thinking abilities, but skill and deep thinking are not always the components of Chess, especially at amateur level and Chess is widely played at amateur and semi-professional level.

So, considering the popularity of the game and the enjoyment it offers, I would like to conclude by saying that both skill and chance make it what it is.

• In every game, there is a certain probability that the 1st player wins. That doesn't make it any game a game of chance. May 10 at 6:34

To say in one line, chess is a game of 100% skill. No chance is involved. This is because both players move the pieces according to their will, without involving some die which eliminates randomness. Secondly, both players can see each other's moves and interpret each other's plans. So chess is a game of skill.

• I am afraid this answer is already given by dfan here. In perfect information games, both players can see each other's moves and interpret each other's plans. Apr 26 at 12:01