"I can't believe it's not winning!"

We all say this at least once in our lives. We misevaluate our position, and miss something obvious or even subtle detail that gives a shocking surprise to you.

For me, this common phrase usually happen in the endgame. I am up material, and/or I have some positional advantage in one form or another, yet I am unable to win, thus I am frusterated with the position and myself.

Here are a couple of very basic King and Pawn endgame positions that I thought to be totally winning at first glance, yet white is unable to win either of them.

Share/give serious examples of your own.

If you are obviously trolling, I don't think it will end well between us.

White is up three pawns, but all he can do is draw.

Here, white is up a pawn and a piece, but a win is impossible.

All I can think of is butter

Um, i disagree, that first position is actually winning for white, 3 pawns and very well positioned king is a bit much dont you think? Especially since white can start with d4 and black cant do much.

I believe this position offers black a better chance of defense, since his king and bishop are placed optimally.

Randomemory et al: FYII haven't examined any of the posted positions here but you can double-check your own analysis (or anyone else's) by using the Nalimov Endgame Tables for any position with 6 or less pieces (except for 5 piece vs one positions)

I set up the 2nd position and it showed White can't win BUT going thru the moves can be quite cumbersome the moves are only displayed one ply at a time - you click on a move and go on to the next ply - and you can't cut and paste the moves either, but it's free so I'm not complaining; You can purchase the Nalimov tables for about $45 and load them into CB or Fritz 

http://www.amazon.com/Endgame-Turbo-Nalimov-Tablebases-DVDs/dp/B0002QUDO0

http://thechessworld.com/resources/nalimov-endgame-tables

@Randomemory: First position is not so surprising, all you need to know to see it quickly is that the following position is a draw:

The first position in post #1, with the passed Pawns on c5 (Black) and f5 (White), is clearly not winning for White. The Pawn on c5 is an outside passed Pawn, which makes it much more valuable than the protected passed Pawn on f5.

A passed Pawn is only dangerous if it can be moved. The f5-Pawn cannot be moved without being lost, because the Black King is well placed.

The c5-Pawn, however, can move and decoy the White King to the Queenside any time Black wants. The Black King cannot be lured away from the square of the f5-Pawn, which will thus never get a chance to promote.

Underestimating the potential of enemy passed Pawns will cause many incorrect evaluations. Something of the sort happened to me to cause me to lose an important tournament game on Chess.com. "A passed Pawn is a criminal [that must] be kept under lock and key." (A. Nimzowitsch)

Move that pawn and the position is really lost for black.

@Sred: If done immediately or rashly, yes. But the presence of the c5-Pawn represents a distraction for White that restricts freedom and prevents him from outpacing the Black King. The passed c5-Pawn must be kept under constant surveillance.

I am not denying that d4, in this case, is a win.  However, I don't trust computers in endgames at all!  Case in point.  Fruit, another computer program, thinks all 3 of these positions are winning for White with White to move.  Only 1 of them is.  I'll let you figure out which one.

This is EXTREMELY FAULTY analysis.

Black is actually weaker than White.  The pawn being outside is not the reason why Black survives, and it's Black that's defending, not White.  The only reason Black is able to draw this is that he is able to maintain opposition.  If White ever was able to wrestle the opposition away from Black, White wins.  The protected passer is stronger than the outside, isolated passer provided the White King is in the box, which it is.  However, Black must blunder in order for that to happen.  For example:  1.Ke3 Ke7 2.Kd3 Kd7 3.Kc3 Kc6?? (3...Kc7, maintaining opposition, is a draw) 4.Kc4! Kb6 5.Kd5 Kb5 6.Kxe5 c4 7.Kd4 Kb4 8.f6 is a win for White.

Yes, but this is no problem at all, because the supported passer doen't need any protection and binds the black king. White can even win both black pawns for his passer, just fails to convert his surviving pawn.

+1

@ThrillerFan: I learned the hard way, even after understanding the fact (albeit clearly not well enough), that outside passed Pawns are stronger than protected passed Pawns. The point is, the position is drawn, because both sides have resources that make the other side defend.

I noticed that 3. ... Kc6?? loses the opposition and the game, but that is an issue that arises only after White tries a certain strategy, that being the Queenside attack. In that case, of course Black must defend properly, or else he loses the isolated (and therefore weak) Pawn and the game.

However, if White blunders by going to the h-file (say, to try to force the f-Pawn through), then the White King would leave the square of the Pawn, losing the game.

So if either side blunders, that side loses, not surprisingly. The upshot is, the given position is a draw, so Black is not really weaker.

For clarity in message 14, I should also add that while Black displays opposition in the position, if White ever does play f6 (say, with the Black King on c7), then as the Black king chases the f-pawn and wins it, White gets both of Black's pawns, but Black still draws as you end up with the position displayed in message 7 with White to move, which is again a draw.  This is a configuration worth knowing.  Any position on the board where Black's King is 2 squares in front of White's King, with White's pawn on the square immediately behind White's King is a draw PROVIDED Black's King is NOT on the back rank with the exception of a8 or h8 AND it is White to move!  If it's Black to move, and it's not a rook pawn, Black is lost.  If Black's king is on b8, c8, d8, e8, f8, or g8 with this configuration, then it doesn't matter who is to move, White or Black, Black is lost!

Here is a FAMOUS one.

I was shocked to see black draw this game honestly....ignore where i started the game, see for yourself.

Any player in their right mind playing White should never move the King to the h-file.  Understanding "the box" is something that you should learn when you are about 1000 in rating.  Take the square the pawn is on (the square in front of the pawn if the pawn is still on its starting square) and draw a diagonal line to the 8th rank (1st rank for Black pawns)  Take the start and end square of that line, and form a box using those as diagonally opposite corners.  When it is the player with the pawn's turn to move, if the opposing king is outside that box, you can promote the pawn just by racing it to the promotion rank, no assistance needed provided it's a King and Pawn ending.  The side with the King should know that it needs to be inside the box in a K+P ending.  This should be the 2nd thing you learn in chess after learning that you must move straight backwards to draw the WKe5, WPe6, BKe7 position with Black to move.

Well NimzoRoy, that is pretty sad.

In the second position, are you 100% sure that only a draw is possible?