Resigning is considered "good manners" in chess. Some players forego them, others are "too nice" (Peter Svidler comes to mind here, having resigned in drawn positions on more than one occasion). In the following position, played by Jonathan, one of the readers of this newsletter, White is completely winning.
He is spoilt for choice. He can play Ke4 or Rc7, picking up the pawn on c4.
Instead, Jonathan's opponent gave check with Ra6.
Nothing wrong with the move, of course, but White missed that if allowed Black has counterplay based on ...Ke5-d4-c3. Of course, that is easily controlled by a move like c3, but good technique in winning positions is always about not allowing (or minimising) counterplay.
Now we come to the intersection of computer and human chess. White continues to be winning even if he allows the black king to come to c3. To a computer it's irrelevant whether it needs to find a single precise winning line or to choose from a variety of winning moves. To a human, it makes all the difference.
As you probably realised by now, White allowed the counterplay, didn't find the precise winning line and eventually the game was drawn. I wonder whether he cursed himself after the game with "how could I not win this position?"
Coming back to the question of resigning, in practice it is based on a feeling. If a player feels that the opponent is not giving any chances and is showing precise technique, when all hope is lost, then resigning is timely. Jonathan admitted that in the above position he would have resigned after Ke4. It would have killed off any hope Black may have had.
However, if there is a feeling that the opponent is not entirely sure what to do and his play seems lax, then resigning would be premature. Small imprecisions can accumulate and suddenly a chance can appear. That is how many lost positions have been saved, by taking those chances that appear when the winning side is not precise.
P.S. This week’s video is one that has been requested numerous times. It serves as a complementary one to my Chessable course King’s Indian Simplified - it deals with the main Anti-King’s Indian attempts by White, like the London System, the Jobava, the Torre Attack and the double fianchetto. Black’s lines are based on the fianchetto of the dark-squared bishop, King’s Indian style, so stay as close as possible to the King’s Indian. Take a look at it here.