user224: In a recent (online) game in which I had black, my opponent played an opening variation with which I was unfamiliar. That, a very aggressive attack, and lack of adequate time to think through my moves had me down a pawn and in poor position as we entered the middle game. While I wasn't yet in major time trouble, they had significantly more time on their clock also.
After a relatively long time before their 15th move, I got the end of game sound and pop up window. The first thing I noticed was that my opponent had taken another pawn and put me in check with their queen. For just an instant, I thought I was being told that I had lost. However, I had multiple ways out of check so knew that couldn't be correct. Then I realized that my opponent had resigned so fast after making their move that the move and end of game signal appeared on my computer simultaneously. Apparently they hadn't seen that I had a knight guarding the square to which they had moved their queen.
Presumably my opponent resigned because they had hung their queen and realized it right after making the move. While that mistake devastated their chances of winning the game, to me it felt unsporting for them to have resigned so abruptly, when many pieces were still on the board (in addition to the two pawns I had lost, the only pieces off the board were from a bishop/knight trade).
Is a resignation like this bad sportsmanship? Or should I just accept it as part of the game after such a significant mistake? (For reference, both of us are rated in the 1100's.)

user23822: It is totally appropriate to resign after you make a major blunder. Playing on in such a situation is implicitly saying that your opponent is a fish.

user2005: I think it’s better, from both a sportsmanship and a gamesmanship perspective, to wait for the opponent to actually move before resigning.  That way the opponent feels more deserving for actually catching the blunder, but also sometimes they won’t catch the blunder and then you can keep playing.

user657: tl;dr No, not bad sportsmanship at all.
Details: When you're sure you're going to lose, why waste your time and your opponent's time? Cash the game in and maybe be able to get in an extra game in whatever playing session you're in? And let your opponent do the same?
My personal practice is I'll resign if I have confidence my opponent knows how to win the position on the board. Sometimes I'll make my opponent play a couple of moves more, just to see if they actually do. Play well enough, and I'll resign; give me a reason to believe you won't, and I'll play on.
I can't speak to what was in your opponent's mind to resign like that, but one possibility is being so angry with themself as to just want the game to be over so they could forget it and move on, and not have to look at that mistake any longer.
On a wider note, this is the first time I've ever heard someone question the sportsmanship of resigning; it's always been complaints about the bad sportsmanship of continuing to play on. (One player, after a blunder, asked if I minded them playing it out, because they wanted to see how a game with that kind of advantage could be won -- young player, advantage was two exchanges. I didn't mind, if you're curious.)

user20819: This issue is not specific to chess. In any game where it can become obvious at some point who will win or lose it is a matter of opinion as to whether the obviously losing side should quit.
The side of "The loser should just quit and we should save ourselves the time or perhaps start a new game" side has fairly logical and straightforward reasoning. It seems other answerers here are in that boat, but it is certainly not an open-shut case.
For many people, not playing until the end ruins the entire game. I generally prefer to play to the very last move, even if it is completely obvious that I will win or lose before then.
If I quit because I'm losing, I feel like I didn't actually lose, I just quit.
If I win because my opponent quits, I feel like I didn't actually beat them, they just quit. This ruins the victory for me. It feels hollow, sometimes worse than not having played at all. It is the other player's right to quit, but it is also my right to be frustrated that they do.
Sometimes I have asked people to please play the last few moves if they quit at a spot that would take less than a minute or two to finish. Just as the loser has the right to not finish, I have the right to ask them to please finish, but I cannot force the matter. I have had people refuse my request to finish, and there is nothing that can be done about it other than politely accepting and walking away annoyed.
There is nothing unsportsmanlike about wanting to finish a game you start. There are plenty of people who feel like they need to finish.
So the summary answer to your question is that it is neither definitely sportsmanlike nor definitely unsportsmanlike. What makes it sporting or not is the manner in which it is done, though in an online game with little or no communication it is mostly a matter of opinion and opinions vary wildly.

user20721: It is good sportsmanship and your opponent would be very happy.
On the other hand, you do not have to do that and are permitted to keep playing without dishonor.  
Indeed I saw an expert toss a queen against a lower rated player and did not resign.  In the end, after a long endgame he managed to win.
He kept improving his position and won some material along the way and was helped by less than good moves by his opponent.
And it depends on the situation too.  You may see you are lost but he may not.  It is always good to have a poker face and keep playing in case they miss the best reply and  you can recover most if not all the ground you lost. 

user20002: You have no way to know what your opponent was thinking. Maybe the move was intended to be a brilliant queen sacrifice, but then he/she realized the flaw in the plan. Or maybe it was just a slip of the mouse!
If it had been my blunder, I would probably have waited to see if you actually took the queen or decided it must be a trap and ignored it, but resigned immediately if you did take it.
I don't think you can draw much conclusion either way about "sportspersonship".

user19877: It is totally normal, and actually, I would consider it good sportsmanship, but that is a bit relative to your level of play.
Among masters, if someone blunders even a piece, they know that their master opponent will have no problem converting, so to play on could be considered rude and a waste of time. That said, they have the right to, and if they do, you don't really complain about it.
At MUCH lower levels, sometimes players are not strong enough to win, even up a queen, so playing on may make sense.
In either case, it is your opponent's right to resign a position they do not want to play. Take the rating points, and smile. 

224: <p>In a recent (online) game in which I had black, my opponent played an opening variation with which I was unfamiliar. That, a very aggressive attack, and lack of adequate time to think through my moves had me down a pawn and in poor position as we entered the middle game. While I wasn't yet in major time trouble, they had significantly more time on their clock also.</p>

<p>After a relatively long time before their 15th move, I got the end of game sound and pop up window. The first thing I noticed was that my opponent had taken another pawn and put me in check with their queen. For just an instant, I thought I was being told that I had lost. However, I had multiple ways out of check so knew that couldn't be correct. Then I realized that my opponent had resigned so fast after making their move that the move and end of game signal appeared on my computer simultaneously. Apparently they hadn't seen that I had a knight guarding the square to which they had moved their queen.</p>

<p>Presumably my opponent resigned because they had hung their queen and realized it right after making the move. While that mistake devastated their chances of winning the game, to me it felt unsporting for them to have resigned so abruptly, when many pieces were still on the board (in addition to the two pawns I had lost, the only pieces off the board were from a bishop/knight trade).</p>

<p>Is a resignation like this bad sportsmanship? Or should I just accept it as part of the game after such a significant mistake? (For reference, both of us are rated in the 1100's.)</p>
 23822: <p>It is totally appropriate to resign after you make a major blunder. Playing on in such a situation is implicitly saying that your opponent is a fish.</p>
 2005: <p>I think it’s better, from both a sportsmanship and a gamesmanship perspective, to wait for the opponent to actually move before resigning.  That way the opponent feels more deserving for actually catching the blunder, but also sometimes they won’t catch the blunder and then you can keep playing.</p>
 657: <p>tl;dr No, not bad sportsmanship at all.</p>

<p>Details: When you're sure you're going to lose, why waste your time and your opponent's time? Cash the game in and maybe be able to get in an extra game in whatever playing session you're in? And let your opponent do the same?</p>

<p>My personal practice is I'll resign if I have confidence my opponent knows how to win the position on the board. Sometimes I'll make my opponent play a couple of moves more, just to see if they actually do. Play well enough, and I'll resign; give me a reason to believe you won't, and I'll play on.</p>

<p>I can't speak to what was in your opponent's mind to resign like that, but one possibility is being so angry with themself as to just want the game to be over so they could forget it and move on, and not have to look at that mistake any longer.</p>

<p>On a wider note, this is the first time I've ever heard someone question the sportsmanship of resigning; it's always been complaints about the bad sportsmanship of continuing to play on. (One player, after a blunder, asked if I minded them playing it out, because they wanted to see how a game with that kind of advantage could be won -- young player, advantage was two exchanges. I didn't mind, if you're curious.)</p>
 20819: <p>This issue is not specific to chess. In any game where it can become obvious at some point who will win or lose it is a matter of opinion as to whether the obviously losing side should quit.</p>

<p>The side of "The loser should just quit and we should save ourselves the time or perhaps start a new game" side has fairly logical and straightforward reasoning. It seems other answerers here are in that boat, but it is certainly not an open-shut case.</p>

<p>For many people, not playing until the end ruins the entire game. I generally prefer to play to the very last move, even if it is completely obvious that I will win or lose before then.</p>

<p>If I quit because I'm losing, I feel like I didn't actually lose, I just quit.</p>

<p>If I win because my opponent quits, I feel like I didn't actually beat them, they just quit. This ruins the victory for me. It feels hollow, sometimes worse than not having played at all. It is the other player's right to quit, but it is also my right to be frustrated that they do.</p>

<p>Sometimes I have asked people to please play the last few moves if they quit at a spot that would take less than a minute or two to finish. Just as the loser has the right to not finish, I have the right to ask them to please finish, but I cannot force the matter. I have had people refuse my request to finish, and there is nothing that can be done about it other than politely accepting and walking away annoyed.</p>

<p>There is nothing unsportsmanlike about wanting to finish a game you start. There are plenty of people who feel like they need to finish.</p>

<p>So the summary answer to your question is that it is neither definitely sportsmanlike nor definitely unsportsmanlike. What makes it sporting or not is the manner in which it is done, though in an online game with little or no communication it is mostly a matter of opinion and opinions vary wildly.</p>
 20721: <p>It is good sportsmanship and your opponent would be very happy.</p>

<p>On the other hand, you do not have to do that and are permitted to keep playing without dishonor.  </p>

<p>Indeed I saw an expert toss a queen against a lower rated player and did not resign.  In the end, after a long endgame he managed to win.
He kept improving his position and won some material along the way and was helped by less than good moves by his opponent.</p>

<p>And it depends on the situation too.  You may see you are lost but he may not.  It is always good to have a poker face and keep playing in case they miss the best reply and  you can recover most if not all the ground you lost. </p>
 20002: <p>You have no way to know what your opponent was thinking. Maybe the move was intended to be a brilliant queen sacrifice, but then he/she realized the flaw in the plan. Or maybe it was just a slip of the mouse!</p>

<p>If it had been my blunder, I would probably have waited to see if you actually took the queen or decided it must be a trap and ignored it, but resigned immediately if you did take it.</p>

<p>I don't think you can draw much conclusion either way about "sportspersonship".</p>
 19877: <p>It is totally normal, and actually, I would consider it good sportsmanship, but that is a bit relative to your level of play.</p>

<p>Among masters, if someone blunders even a piece, they know that their master opponent will have no problem converting, so to play on could be considered rude and a waste of time. That said, they have the right to, and if they do, you don't really complain about it.</p>

<p>At MUCH lower levels, sometimes players are not strong enough to win, even up a queen, so playing on may make sense.</p>

<p>In either case, it is your opponent's right to resign a position they do not want to play. Take the rating points, and smile. </p>
