How to lose quickly - Jumping in

There is nothing more annoying or disappointing to a chess player than losing a won game.  That is losing a game where you had a massive advantage.

I'm playing Black in the position below.  Take a look and try and see why I think Black is better.

Black has the move and some big advantages.  His rooks dominate the d-file and his queen and knight are both waiting to jump into an attack on White's king.  White can't complete his development easily as his bishop is in the way of connecting the rooks and needs to find an active role, but both d2 and e3 are off limits.  His king is rather awkwardly placed on h1 and doesn't have a move, which is never a good sign.
White has just moved his queen to e2 and is attacking the Black knight. In the game I played
25...Nf2+? 26.Rxf2 Qxf2, 27.Qxf2 Rd1+

Now I was surprised to see that 28.Qg1 loses Black a piece.  After 28...Rxg1 29.Kxg1 the White king will not be mated on the back rank with 29...Rd1+, as I had thought on move 25.  Play continued, but White soon activated his extra material and won.  What went wrong?

I call this type of error "jumping in".  You see a line with a forcing sequence from a strong position that appears to win and instead of making 100% sure that it does win you dive in and 'snatch' at the full point.

What is the answer?  Cold hard analysis.  Dan Heisman at the marvellous Chesscafe site talks about this type of error and says you should try and analyse the moves until the position is quiet, that is no more forcing moves http://www.chesscafe.com/text/heisman55.pdf.

If you think you are close to winning then its worth spending extra time checking your analysis.  If you do look at a line and can't see all the possibilities then look for other simpler lines.

Two other moves that jump out to me are 25...Nf6 and 25...Rd1.
25...Nf6 takes the knight out of the sights of White's queen, but the immediate attack would be over, so this line would be the last to look at.

25...Rd1.  The first point is that 26.Rxd1 Rxd1+ 27.Qxd1 allows Black the knight fork 27...Nf2+ winning the white queen

Analysis

Let us call 25...Rd1 line 2, we have established that White can not simply take the rook.

White can't take the knight either as Rxf1 is mate.  White therefore has to find a way to stop 26...Rxf1, 27.Qxf1 Nf2+, 28.Kg1 Nh3+ winning a piece.  White either has to connect the rooks to offer himself extra back rank protection, or defend f2.
Connect the rooks, perhaps White could try 26.Bxf5, but 26...Rxa1 forces 27.Rxa1 and then ...Nf2+, 28.Kg1 Nh3+, 29.Kh1 Nxf4 - Note how this discovery trick crops up again and again. - wins a piece for White and stops any queen invasion on h5

Analysis

Defend f2, 26.Nh3, this is probably White's best.  26...Rxf1+, 27.Qxf1 takes the threat from Black's knight and Black can introduce new back rank threats with 27...Qb5

Analysis

I think I have shown that line 2 offers Black a big advantage.  My problem during the game was that I didn't really look further line 1, I just 'jumped in'.  Earlier I said that "Cold hard analysis" was the answer and perhaps you thought that glib, well I would agree.  Often its difficult to see the truth to a line of play and its so easy to go wrong.  What I would say is this

• Take your time and analyse as deeply as possible if you think you may have a winning line

Try to find alternatives, especially if your first line involves giving up any material.  The second line may give the same result without the material risk.  Which is my second point.

• Given a choice, play the line with the least risk