user24734: Consider below games where white looses a clean rook quite early in the opening but fights on hoping that they will be lucky and escape. Lucky enough, they escape and win the clearly lost game.
[Event "Rated Blitz game"]
[Result "1-0"]
[Variant "Standard"]
[TimeControl "300+0"]
[ECO "B21"]
[Opening "Sicilian Defense: McDonnell Attack"]
[Termination "Normal"]
[Annotator "lichess.org"]
[FEN ""]

1. e4 c5 2. f4 { B21 Sicilian Defense: McDonnell Attack } d5 3. e5 Bf5 4. d3 d4 5. g4 Bd7 6. f5 e6 7. Qf3 Bc6 8. Qf2 Bxh1 9. Bg2 Bxg2 10. Qxg2 Nc6 11. Nd2 Qh4+ 12. Kf1 exf5 13. gxf5 Nh6 14. Ngf3 Qg4 15. Qh1 Qxf5 16. b3 Be7 17. Bb2 Nxe5 18. Re1 Bd6 19. c3 O-O 20. cxd4 cxd4 21. Kg2 Qg4+ 22. Kf2 Qf4 23. Re4 Nxd3+ 24. Ke2 Nxb2 25. Rxf4 d3+ 26. Ke3 Rfe8+ 27. Ne4 f5 28. Rh4 fxe4 29. Ng5 Nf5+ 30. Kd2 e3+ 31. Kc3 Be5+ 32. Kb4 Nxh4 33. Qd5+ Kh8 34. Nf7+ Kg8 35. Nh6+ { Black resigns. } 1-0

I have heard in the past that 'It is noble to resign' but if we fight on the stars may be aligned and luck come our way. Can we say that using luck may work as a strategy?

user26162: How does one actually use luck?
In game theory a lot of real world data is discarded in favor of simplifying the problem we are trying to model (and usually it is assumed both players play to the best of their abilities). A lot of things that affect both players are ignored, because they are not easy to model. Such things are: concentration, familiarity with positions, preferences, skill with each piece, memory, time, etc.
Another important point is that player skill is not something static, ratings should always be considered estimates of true skill, which is pretty difficult to measure since it can vary from game to game and even during a game. But it can be said that highly skilled players commit fewer mistakes than less skilled players.
In other words, it can be said that we are hoping our opponents commit mistakes we can identify and exploit in all games, so in this sense, all players could be said to be always trying to or using their luck all the time and the fact that a player committed one or more bad moves doesn't change that. To notice a mistake committed by an opponent is another one of those skills that are difficult to measure, so is the skill to punish a mistake.
Luck as randomness
White could have lost the game, it also could have ended in a draw. There was no guarantee that 'luck' or randomness would be 'in favor' of any player. So just as white gambled and won, it could have been a loss instead.
In this sense, no player can actually use luck, because it is not a component a player has any control over as both players are subject to randomness.
The place of sportsmanship
That being said, what role does sportsmanship play? In my opinion sportsmanship plays the role of respect/politeness. During a game, if both players agree the game is over and its result, wouldn't it be better to just start a new one? It's another thing entirely if there is no agreement. And the reason for both players not agreeing doesn't matter, though agreeing on the result is just usually faster.

user7002: Just a few examples of GMs talking about luck in chess.
Kasparov: in chess everything is visible but the result is random (as opposite of election in Russia, where everything is hidden but the result is certain).
Seirawan: it's very hard to win a winning game. If I can win all those winning positions, my rating points would be 200 higher.
Tal: Some sacrifices are sound, the rest are mine.
You would also remember women world champion Ushenina failed to deliver B+N checkmate.
I myself once lost a game like this
[fen "1r3k2/p4pp1/8/8/8/P7/KPQ3P1/6q1 w - - 0 1"]

1. Qc5+! Kg8?? 2. Qxg1

So randomness is actually part of the game and try your luck by all means.

user24572: There are times when adding a random variable to a game of skill can actually help:
Let's take a simple example with the game even and odds.  In this game you and your opponent hold up one or two fingers at the same time. If the total is even one person wins and odd the other. Let's say your opponent is really good at getting into your head and they are winning about 75 percent of the time.  They decide to make a bet: if you win you get $1.10 and if they win they get $1.
Obviously if everything continues as before you will probably lose a lot of money but there's an easy trick you can use that guarantees your success in the long run: flip a coin.  By doing so you've introduced a random variable ( that has variance, also known as luck) that completely eliminates their skill based advantage!  You can also use this approach in poker when facing a far more skilled opponent.  In fact, more experienced poker players often find it easier to play someone slightly worse than them compared to a complete beginner exactly because they are so unpredictable.
All that being said, these examples are of games where there is a large amount of randomness built in, you are given incomplete information, and you are given favorable odds.  I think it would be very hard to work this approach into chess, which is a very different beast.
Note: the examples here are roughly paraphrased from a poker book by poker expert Sklansky.

user7657: Well, you can't plan on luck.  Either it happens or it doesn't.  It could also be bad luck for that matter, so I wouldn't rely on it to win any games.  As far as resigning prematurely is concerned, that can be a mistake if you still have some fighting chances.  It was Tartakower I believe who said you can't win by resigning. But they have to be legitimate chances based upon your situation in the game.  If you're in a hopeless king and and pawn ending for example, that can be insulting to a decent opponent if you refuse to resign. But if you'e only down a minor piece early in the game and have no other weaknesses, I certainly wouldn't resign then but would keep making the best moves I could, which I have done in some games favorably.  Then your opponent could potentially blunder.  If that's what you refer to as luck, then I won't argue with you.

user11144: "Luck" is a bad wording. You can "push your luck", though.

If you are a good tactician, and preferrable your opponent isn't,
turn the board into chaos. I won games a rook down and no real
swindling chances that way, and am reknowned as being lucky.
Fight. GM Niclas Huschenbeth is a well known "lucky" fighter. I had him
on the verge of loss about each time we played, and if I were a GM myself,
probably I would have won each time. Most other GMs (even knowing my
renommee as occasional GM killer) would have soiled their pants
and offered me a draw. Not Niclas.
Just by pure statistical variance, some people seem to be "lucky".
A whole book "Luck in Chess" was written by Edward Winter, it might
interested you (and I think it isn't the only one on that sujet.)


user25322: No, luck cannot be used as a strategy, as by definition luck is randomly distributed and outside of your volition; whereas conversely by definition a strategy is some method or plan designed and deployed under your volition to gain advantage.

user17254: Relying on luck as a strategy may work, but not as often as sound calculation and intuition. Therefore, luck should not be your primary strategy.
As another answer said, chess is a game of perfect information, so luck would arguably only exist in the inaccuracies committed by players who are making suboptimal moves. These could be called unlucky, or random.
However, the context of your question is about deciding whether to resign or play on when you have lost significant material or reached a clearly losing position. Asking yourself these questions can help you make that decision:

How much time remains in the game? In shorter time controls where there is no increment, or if there remains, say, less than 5 minutes on their clock, even a strong opponent can blunder: lucky for you! So it may be worth playing on and trying to complicate and confuse the position to induce them to make a mistake.
How strong is your opponent compared to you? If you are both amateur or untitled players, say, below 2000 rating, or if your opponent is much weaker than you, there is a higher chance of a blunder that could reverse the position.
Is this game part of a match? If you have many more games to play, you may want to conserve your energy by resigning and focusing on the next game, where you'll have a fresh start.
Is this just a game for fun? To some extent, all chess games should be for fun. But in a more serious game, you might want to press on, especially if there is a prize on the line.


user15337: Clearly the situation you describe has nothing to do with luck. Instead, it is simply bad play by black who cannot turn a decisive advantage into a victory.
The question in the text is actually:
Are you allowed to make strategic use of your opponent's weaknesses? The answer is of course "yes, absolutely!". But framed this way it becomes clear just why it is bad sportsmanship not to resign when one has clearly lost: Because it betrays that you think your opponent is an idiot. Consequently not resigning becomes worse sportsmanship with better opponents. (As an aside, in the game of Go an entirely decided game can be drawn out for a long time if the loser refuses to accept defeat which is therefore much more annoying than in chess.)
An interesting side question is: Is there at all a luck component in chess? It seems obvious that there isn't because chess is a complete information game with no random input. But I'd make the case that there is something resembling luck because while all information is available — after all, the board is right there! — the path of perfectly utilizing that information is not. Chess is not solved. That means that our assessment of positions is imperfect. The superiority of one move over another may only become apparent later. It was always superior, mind you; but we didn't know. This is where luck comes in: We may be lucky and choose a move that later turns out to be great. This kind of luck plays a greater role with weak players whose positional knowledge and analytic capacity is limited. Chances are that a strong player would have recognized the superior move — in fact, this ability is what defines a strong player.
Now to your title question: Can this kind of luck be used as a strategy against a stronger player? That is questionable. It won't work in simple positions with clear paths forward: Those will be understood well by the strong player, hence there will be no bad surprises for them later. This kind of luck therefore can only work in complex positions in which even the strong player's predictive depth is limited. But unfortunately even the limited prediction, the intuition and the experience favor the strong player in complex positions. A weak player with an inferior understanding of the complex position will have a hard time conjuring up a lucky turn that the strong player could not prevent in time.

user16910: I believe there are quite a few distinct points to make to properly answer the question. @QueensKnight already adressed the "playing in a lost position" part of your question, so I'll focus on the "luck as a strategy" part.
1) Strategy hinges on reducing unknown or uncontrollable factors
When making a plan to achieve a certain goal (in chess or in life), it's important to make sure that it can be relied on at any point, otherwise there would be no point in following it. Often, it's impossible to guarantee the result because some factors escape our knowledge or our detection, but despite that minimizing such factors remains the best way to improve the strategy, by reducing odds of undesired outcome from unexpected events.
In stark contrast, relying on luck takes the exact opposite approach : decide nearly nothing to achieve the goal, hoping to reach it through favorable coincidences. Whether a good thing or not, it's clear that following this pattern is too different from a strategy to be called such.
2) Chess is a deterministic, perfect information game
When two persons play a game of chess, every move has always predictable impacts on the board. Pieces always move the same way, and capture the same way, pawns promotion condition and choices are the same, checkmate is always an inescapable check to the King, and so on. Furthermore, no information is hidden from either player : they see both their and their opponent's pieces at any time, see every move, and can contemplate their position as long as their clock time allows before the next move.
So under these conditions, there is simply no place for luck to occur inside the game, as there's neither random elements, nor unpredictability from lack of information. Hence, it makes little sense to play random moves when, at least in purely theoretical conditions, it's possible to analyze every variation down to their final result to give them as objective an evaluation as possible.
3) Playing the game or playing the player?
There is however one crucial factor that decides how a game of chess proceeds : both players. Chess is not an abstract thought experiment, but a concrete event shaped by the players. Of course, humans and machines alike have yet to solve chess, and even then it's not trivial to approximately evaluate a position at any level (depending on your error tolerance). This means that both players must carefully analyze the board to find which move they prefer, when they could play any move at all.
This gives room for outcomes that would defy the logic of "both sides play perfectly". Here are a few examples :

Loss of focus : One player misses a possibility in a deep variation because they failed to consider it at all.

Exhaustion : After playing for hours, a player cuts their evaluation short because they're too tired to think further (the risk of erroneous conclusions would be too high).

Overconfidence : A player doesn't deem it necessary to analyze a position further, because it appears good enough at first glance, or because they believe their previous analysis, despite not being exhaustive until the final result, is still valid and isn't worth updating.

Distraction : An event happens outside of the game that catches the player's attention (could be as simple as thinking about lunch), interrupting their thought process; when they resume their analysis, though it's not always the case, they might forget some important detail they had uncovered earlier.


And so on. Because the execution of each move in the game isn't guarantee, if only from the psychological side, and because it's not realistic to guess the opponent's mind (chess would be quite boring otherwise), there's room to believe the opponent could slip up for such reasons, which is what "being lucky" in chess really means.
Conclusion
There's no luck in the game of chess itself, and even if there was, counting on it rather than doing everything possible to reduce losing odds can't be qualified as a strategy. From this, I'd say that luck cannot work as a strategy. However, it's not possible to tell either what's the opponent's state of mind (outside of very obvious clues), so there's always the possibility that they could make an uncharacteristic blunder for a variety of plausible, human reasons. Which means luck plays a role at the human level.
So it's true that that as long as you play, there's still at least a small possibility to win, while resigning will always be a loss. Still, no matter if there's the slimmest of chance for such a "lucky win", remember that it's not only out of your control, but there are the same chances that you could be affected by it in the opposite way get an "unlucky loss" (I know I've had my fair share of blunders that I'd readily qualify as such on the mental aspect). Is it worth spending time moving pieces hoping for the best then?
I'd suggest, when you're in a lost position and willing to play further, instead of just hoping for a blunder from the opponent, to try your best, keep a positive attitude, and hang on in the game. Sure, the opponent might still blunder, but they're far more likely to play well until the end (and the gap for this likelihood widens with the player's rating). But a very important thing in chess aside from winning is learning. Try to survive as long as possible after a big mistake. Try not to make another. Pay attention to the board and your mindset. If your opponent could mess up and lose the advantage if they don't find the one good move in a certain variation, try it out (forcing them to demonstrate their ability at converting an advantage, see @QueensKnight 's answer). Just do your best and learn from it. This will 100% be more valuable than simply hoping for a "lucky" outcome.

user16758: Whether or not to resign is a question of sportsmanship rather than strategy, I would argue. Just according to the rules, you are never forced to resign and can play on until you are checkmated (or someone is stalemated). However, it is expected (to a certain degree) that you resign in a position that is "clearly" lost.
There is no definite definition when a position is "clearly" lost though. If I am down a rook against Magnus Carlsen, I would definitely resign, because the chances of Carlsen blundering and giving me an opportunity to turn the game are infinitesimally small. Similarly, if Carlsen were able to gain a pawn without me gaining any compensation for it, I might resign as well (especially if it were the endgame). Again, Carlsen is expected to turn this advantage into a win eventually, and hoping that he will make an unrealistic mistake would be poor sportsmanship. On the other hand, if I was playing an opponent of my strength level, then a single pawn advantage might not be enough for him to find the win (even though the game might be already lost at perfect play). Instead, I would continue playing against my opponent until he demonstrated that he is aware of how to utilize the advantage to create a win (e.g., by creating a passed pawn that I can only stop by sacrificing another piece).

24734: <p>Consider below games where white looses a clean rook quite early in the opening but fights on hoping that they will be lucky and escape. Lucky enough, they escape and win the clearly lost game.</p>
<pre><code>[Event &quot;Rated Blitz game&quot;]
[Result &quot;1-0&quot;]
[Variant &quot;Standard&quot;]
[TimeControl &quot;300+0&quot;]
[ECO &quot;B21&quot;]
[Opening &quot;Sicilian Defense: McDonnell Attack&quot;]
[Termination &quot;Normal&quot;]
[Annotator &quot;lichess.org&quot;]
[FEN &quot;&quot;]

1. e4 c5 2. f4 { B21 Sicilian Defense: McDonnell Attack } d5 3. e5 Bf5 4. d3 d4 5. g4 Bd7 6. f5 e6 7. Qf3 Bc6 8. Qf2 Bxh1 9. Bg2 Bxg2 10. Qxg2 Nc6 11. Nd2 Qh4+ 12. Kf1 exf5 13. gxf5 Nh6 14. Ngf3 Qg4 15. Qh1 Qxf5 16. b3 Be7 17. Bb2 Nxe5 18. Re1 Bd6 19. c3 O-O 20. cxd4 cxd4 21. Kg2 Qg4+ 22. Kf2 Qf4 23. Re4 Nxd3+ 24. Ke2 Nxb2 25. Rxf4 d3+ 26. Ke3 Rfe8+ 27. Ne4 f5 28. Rh4 fxe4 29. Ng5 Nf5+ 30. Kd2 e3+ 31. Kc3 Be5+ 32. Kb4 Nxh4 33. Qd5+ Kh8 34. Nf7+ Kg8 35. Nh6+ { Black resigns. } 1-0
</code></pre>
<p>I have heard in the past that '<strong>It is noble to resign</strong>' but if we fight on the stars may be aligned and luck come our way. Can we say that using luck may work as a strategy?</p>
 26162: <h2>How does one actually <em>use</em> luck?</h2>
<p>In game theory a lot of real world data is discarded in favor of simplifying the problem we are trying to model (and usually it is assumed both players play to the best of their abilities). A lot of things that affect both players are ignored, because they are not easy to model. Such things are: concentration, familiarity with positions, preferences, skill with each piece, memory, time, etc.</p>
<p>Another important point is that player skill is not something static, ratings should always be considered estimates of true skill, which is pretty difficult to measure since it can vary from game to game and even during a game. But it can be said that highly skilled players commit fewer mistakes than less skilled players.</p>
<p>In other words, it can be said that we are hoping our opponents commit mistakes we can identify and exploit in all games, so in this sense, <strong>all players could be said to be always trying to or using their luck all the time</strong> and the fact that a player committed one or more bad moves doesn't change that. To notice a mistake committed by an opponent is another one of those skills that are difficult to measure, so is the skill to punish a mistake.</p>
<h2>Luck as randomness</h2>
<p>White could have lost the game, it also could have ended in a draw. There was no guarantee that 'luck' or randomness would be 'in favor' of any player. So just as white gambled and won, it could have been a loss instead.</p>
<p>In this sense, <strong>no player can actually <em>use</em> luck</strong>, because it is not a component a player has any control over as both players are subject to randomness.</p>
<h2>The place of sportsmanship</h2>
<p>That being said, what role does sportsmanship play? <em>In my opinion</em> sportsmanship plays the role of respect/politeness. During a game, if <strong>both</strong> players agree the game is over and its result, wouldn't it be better to just start a new one? It's another thing entirely if there is no agreement. And the reason for both players not agreeing doesn't matter, though agreeing on the result is just usually faster.</p>
 7002: <p>Just a few examples of GMs talking about luck in chess.</p>
<p>Kasparov: in chess everything is visible but the result is random (as opposite of election in Russia, where everything is hidden but the result is certain).</p>
<p>Seirawan: it's very hard to win a winning game. If I can win all those winning positions, my rating points would be 200 higher.</p>
<p>Tal: Some sacrifices are sound, the rest are mine.</p>
<p>You would also remember women world champion Ushenina failed to deliver B+N checkmate.</p>
<p>I myself once lost a game like this</p>
<pre><code>[fen &quot;1r3k2/p4pp1/8/8/8/P7/KPQ3P1/6q1 w - - 0 1&quot;]

1. Qc5+! Kg8?? 2. Qxg1
</code></pre>
<p>So randomness is actually part of the game and try your luck by all means.</p>
 24572: <p>There are times when adding a random variable to a game of skill can actually help:</p>
<p>Let's take a simple example with the game even and odds.  In this game you and your opponent hold up one or two fingers at the same time. If the total is even one person wins and odd the other. Let's say your opponent is really good at getting into your head and they are winning about 75 percent of the time.  They decide to make a bet: if you win you get $1.10 and if they win they get $1.</p>
<p>Obviously if everything continues as before you will probably lose a lot of money but there's an easy trick you can use that guarantees your success in the long run: flip a coin.  By doing so you've introduced a random variable ( that has variance, also known as luck) that completely eliminates their skill based advantage!  You can also use this approach in poker when facing a far more skilled opponent.  In fact, more experienced poker players often find it easier to play someone slightly worse than them compared to a complete beginner exactly because they are so unpredictable.</p>
<p>All that being said, these examples are of games where there is a large amount of randomness built in, you are given incomplete information, and you are given favorable odds.  I think it would be very hard to work this approach into chess, which is a very different beast.</p>
<p>Note: the examples here are roughly paraphrased from a poker book by poker expert Sklansky.</p>
 7657: <p>Well, you can't plan on luck.  Either it happens or it doesn't.  It could also be bad luck for that matter, so I wouldn't rely on it to win any games.  As far as resigning prematurely is concerned, that can be a mistake if you still have some fighting chances.  It was Tartakower I believe who said you can't win by resigning. But they have to be legitimate chances based upon your situation in the game.  If you're in a hopeless king and and pawn ending for example, that can be insulting to a decent opponent if you refuse to resign. But if you'e only down a minor piece early in the game and have no other weaknesses, I certainly wouldn't resign then but would keep making the best moves I could, which I have done in some games favorably.  Then your opponent could potentially blunder.  If that's what you refer to as luck, then I won't argue with you.</p>
 11144: <p>&quot;Luck&quot; is a bad wording. You can &quot;push your luck&quot;, though.</p>
<ul>
<li>If you are a good tactician, and preferrable your opponent isn't,
turn the board into chaos. I won games a rook down and no real
swindling chances that way, and am reknowned as being lucky.</li>
<li>Fight. GM Niclas Huschenbeth is a well known &quot;lucky&quot; fighter. I had him
on the verge of loss about each time we played, and if I were a GM myself,
probably I would have won each time. Most other GMs (even knowing my
renommee as occasional GM killer) would have soiled their pants
and offered me a draw. Not Niclas.</li>
<li>Just by pure statistical variance, some people seem to be &quot;lucky&quot;.</li>
<li>A whole book &quot;Luck in Chess&quot; was written by Edward Winter, it might
interested you (and I think it isn't the only one on that sujet.)</li>
</ul>
 25322: <p>No, luck cannot be used as a strategy, as by definition luck is randomly distributed and <em>outside of your volition</em>; whereas conversely by definition a strategy is some method or plan designed and deployed <em>under your volition</em> to gain advantage.</p>
 17254: <p>Relying on luck as a strategy <strong>may</strong> work, but not as often as sound calculation and intuition. Therefore, <strong>luck should not be your primary strategy</strong>.</p>
<p>As another answer said, chess is a game of perfect information, so luck would arguably only exist in the inaccuracies committed by players who are making suboptimal moves. These could be called unlucky, or random.</p>
<p>However, the context of your question is about deciding whether to resign or play on when you have lost significant material or reached a clearly losing position. Asking yourself these questions can help you make that decision:</p>
<ul>
<li><strong>How much time remains in the game?</strong> In shorter time controls where there is no increment, or if there remains, say, less than 5 minutes on their clock, even a strong opponent can blunder: <em>lucky</em> for you! So it may be worth playing on and trying to complicate and confuse the position to induce them to make a mistake.</li>
<li><strong>How strong is your opponent compared to you?</strong> If you are both amateur or untitled players, say, below 2000 rating, or if your opponent is much weaker than you, there is a higher chance of a blunder that could reverse the position.</li>
<li><strong>Is this game part of a match?</strong> If you have many more games to play, you may want to conserve your energy by resigning and focusing on the next game, where you'll have a fresh start.</li>
<li><strong>Is this just a game for fun?</strong> To some extent, <em>all</em> chess games should be for fun. But in a more serious game, you might want to press on, especially if there is a prize on the line.</li>
</ul>
 15337: <p><strong>Clearly the situation you describe has nothing to do with luck.</strong> Instead, it is simply bad play by black who cannot turn a decisive advantage into a victory.</p>
<p>The question in the text is actually:</p>
<p><strong>Are you allowed to make strategic use of your opponent's weaknesses?</strong> The answer is of course &quot;yes, absolutely!&quot;. But framed this way it becomes clear just why it is bad sportsmanship not to resign when one has clearly lost: <em>Because it betrays that you think your opponent is an idiot.</em> Consequently not resigning becomes worse sportsmanship with better opponents. (As an aside, in the game of Go an entirely decided game can be drawn out for a long time if the loser refuses to accept defeat which is therefore much more annoying than in chess.)</p>
<p>An interesting side question is: <strong>Is there at all a luck component in chess?</strong> It seems obvious that there isn't because chess is a complete information game with no random input. But I'd make the case that there is something <em>resembling</em> luck because while all information is available — after all, the board is right there! — the path of perfectly <em>utilizing</em> that information is <em>not.</em> <strong>Chess is not solved.</strong> That means that our assessment of positions is imperfect. The superiority of one move over another may only become apparent later. It was always superior, mind you; but we didn't know. This is where luck comes in: We may be lucky and choose a move that later turns out to be great. This kind of luck plays a greater role with weak players whose positional knowledge and analytic capacity is limited. Chances are that a strong player would have recognized the superior move — in fact, this ability is what defines a strong player.</p>
<p>Now to your title question: <strong>Can this kind of luck be used as a strategy against a stronger player?</strong> That is questionable. It won't work in simple positions with clear paths forward: Those will be understood well by the strong player, hence there will be no bad surprises for them later. This kind of luck therefore can only work in complex positions in which even the strong player's predictive depth is limited. But unfortunately even the limited prediction, the intuition and the experience favor the strong player in complex positions. A weak player with an inferior understanding of the complex position will have a hard time conjuring up a lucky turn that the strong player could not prevent in time.</p>
 16910: <p>I believe there are quite a few distinct points to make to properly answer the question. @QueensKnight already adressed the &quot;playing in a lost position&quot; part of your question, so I'll focus on the &quot;luck as a strategy&quot; part.</p>
<h2>1) Strategy hinges on reducing unknown or uncontrollable factors</h2>
<p>When making a plan to achieve a certain goal (in chess or in life), it's important to make sure that it can be relied on at any point, otherwise there would be no point in following it. Often, it's impossible to guarantee the result because some factors escape our knowledge or our detection, but despite that minimizing such factors remains the best way to improve the strategy, by reducing odds of undesired outcome from unexpected events.</p>
<p>In stark contrast, relying on luck takes the exact opposite approach : decide nearly nothing to achieve the goal, hoping to reach it through favorable coincidences. Whether a good thing or not, it's clear that following this pattern is too different from a strategy to be called such.</p>
<h2>2) Chess is a deterministic, <a href="https://en.wikipedia.org/wiki/Perfect_information" rel="noreferrer">perfect information</a> game</h2>
<p>When two persons play a game of chess, every move has always predictable impacts on the board. Pieces always move the same way, and capture the same way, pawns promotion condition and choices are the same, checkmate is always an inescapable check to the King, and so on. Furthermore, no information is hidden from either player : they see both their and their opponent's pieces at any time, see every move, and can contemplate their position as long as their clock time allows before the next move.</p>
<p>So under these conditions, there is simply no place for luck to occur inside the game, as there's neither random elements, nor unpredictability from lack of information. Hence, it makes little sense to play random moves when, at least in purely theoretical conditions, it's possible to analyze every variation down to their final result to give them as objective an evaluation as possible.</p>
<h2>3) Playing the game or playing the player?</h2>
<p>There is however one crucial factor that decides how a game of chess proceeds : both players. Chess is not an abstract thought experiment, but a concrete event shaped by the players. Of course, humans and machines alike have yet to solve chess, and even then it's not trivial to approximately evaluate a position at any level (depending on your error tolerance). This means that both players must carefully analyze the board to find which move they prefer, when they could play any move at all.</p>
<p>This gives room for outcomes that would defy the logic of &quot;both sides play perfectly&quot;. Here are a few examples :</p>
<ul>
<li><p>Loss of focus : One player misses a possibility in a deep variation because they failed to consider it at all.</p>
</li>
<li><p>Exhaustion : After playing for hours, a player cuts their evaluation short because they're too tired to think further (the risk of erroneous conclusions would be too high).</p>
</li>
<li><p>Overconfidence : A player doesn't deem it necessary to analyze a position further, because it appears good enough at first glance, or because they believe their previous analysis, despite not being exhaustive until the final result, is still valid and isn't worth updating.</p>
</li>
<li><p>Distraction : An event happens outside of the game that catches the player's attention (could be as simple as thinking about lunch), interrupting their thought process; when they resume their analysis, though it's not always the case, they might forget some important detail they had uncovered earlier.</p>
</li>
</ul>
<p>And so on. Because the execution of each move in the game isn't guarantee, if only from the psychological side, and because it's not realistic to guess the opponent's mind (chess would be quite boring otherwise), there's room to believe the opponent could slip up for such reasons, which is what &quot;being lucky&quot; in chess really means.</p>
<h2>Conclusion</h2>
<p>There's no luck in the game of chess itself, and even if there was, counting on it rather than doing everything possible to reduce losing odds can't be qualified as a strategy. From this, I'd say that <strong>luck cannot work as a strategy</strong>. However, it's not possible to tell either what's the opponent's state of mind (outside of very obvious clues), so there's always the possibility that they could make an uncharacteristic blunder for a variety of plausible, human reasons. Which means <strong>luck plays a role at the human level</strong>.</p>
<p>So it's true that that as long as you play, there's still at least a small possibility to win, while resigning will always be a loss. Still, no matter if there's the slimmest of chance for such a &quot;lucky win&quot;, remember that it's not only out of your control, but there are the same chances that you could be affected by it in the opposite way get an &quot;unlucky loss&quot; (I know I've had my fair share of blunders that I'd readily qualify as such on the mental aspect). Is it worth spending time moving pieces hoping for the best then?</p>
<p>I'd suggest, when you're in a lost position and willing to play further, instead of just hoping for a blunder from the opponent, to try your best, keep a positive attitude, and hang on in the game. Sure, the opponent might still blunder, but they're far more likely to play well until the end (and the gap for this likelihood widens with the player's rating). But a very important thing in chess aside from winning is <strong>learning</strong>. Try to survive as long as possible after a big mistake. Try not to make another. Pay attention to the board and your mindset. If your opponent could mess up and lose the advantage if they don't find the one good move in a certain variation, try it out (forcing them to demonstrate their ability at converting an advantage, see @QueensKnight 's answer). Just do your best and learn from it. This will 100% be more valuable than simply hoping for a &quot;lucky&quot; outcome.</p>
 16758: <p>Whether or not to resign is a question of sportsmanship rather than strategy, I would argue. Just according to the rules, you are never forced to resign and can play on until you are checkmated (or someone is stalemated). However, it is expected (to a certain degree) that you resign in a position that is &quot;clearly&quot; lost.</p>
<p>There is no definite definition when a position is &quot;clearly&quot; lost though. If I am down a rook against Magnus Carlsen, I would definitely resign, because the chances of Carlsen blundering and giving me an opportunity to turn the game are infinitesimally small. Similarly, if Carlsen were able to gain a pawn without me gaining any compensation for it, I might resign as well (especially if it were the endgame). Again, Carlsen is expected to turn this advantage into a win eventually, and hoping that he will make an unrealistic mistake would be poor sportsmanship. On the other hand, if I was playing an opponent of my strength level, then a single pawn advantage might not be enough for him to find the win (even though the game might be already lost at perfect play). Instead, I would continue playing against my opponent until he demonstrated that he is aware of how to utilize the advantage to create a win (e.g., by creating a passed pawn that I can only stop by sacrificing another piece).</p>
