Here is a game I lost against a bad opening. However it looks like I lost to tactics in the middlegame and couldn't keep my space advantage.

I see two things that turned this game suddenly. Move 13. Rhe1 allowed him to fork two of your pawns. It usually starts small and goes from there. Moving your pawn to f3 would have prevented that.Doing so would have helped keep his knight immobile on that side of the board.

After choosing to castle queen side, you should have made it a priority to plan to not only limit the mobility of your opponent on your king side with your pawns, but to begin to advance them for an overwhelming attack against your opponents king side pawns.

I think you castled behind a weaker structure, than on your king's side. It is 4 pawns to 2, on that side of the board. You needed to act fast and be decisive to take advantage of the 5 to 3 in your favor on the kingside.

Though I love to castle opposite of my opponent purposely, as a strategy in mind from my first move. I have learned to not force it, if it isn't there. If you don't have a good, fast acting plan in place to both attack and defend, the two tempos you lose trying to get your king to a safe square can be absolutely detrimental.

Though he didn't take the initial pawn, the fact his knight was easily able to start a relentless attack helped to gain your opponent an exchange in his favor. The pawn advance I had proposed earlier would have also not only prevented this series of knight moves, but would have probably took away many other opportunities for your opponent too, even with his other pieces, because he would have been too busy trying to defend.

Once he had the advantage in time and material, he started trading. You have to be careful to not let your opponent have easy access to your pieces if possible in close games or when you get behind. They can simplify and take away any tactical options you might have had, while they help to limit their chances for mistakes too.

So you played a standard Scotch with a tempo up.

But unfortunately you failed to get anything out of it.

You spoiled it already at move 8: Bxd4??

Why is this move so bad?

When you have space advantage you shouldn't exchange. Space advantage is good because it restricts your opponent's pieces. The more pieces, the bigger the restriction. So don't exchange. It helps your opponent. Needless to say that 9.Qxd4 wasn't very bright either.

After exchanging queens and two pairs of minors, your space advantage and ideal centre were worth nothing. Black could have fully equalised with 10...d6.

Strange that you refused to kick around his knight with 11.e5.

@namenoIhad:

Please don't write things like "Move 13. Rhe1 allowed him to fork two of your pawns." What, in your opinion, would have been the consequences of 14.f3? Considering these consequences, do you still think that criticising 13.Rhe1 is justified?

Also, I am not convinced that your reflections on opposite castling have any bearing in this particular game. The material was already too reduced.

SInce you obviously think that your rating or mine suddenly makes anything I had to say about the situation wrong...

I will ask you a rhetorical question, because I think it is the only way to get my point across.

Do you think it was a good idea to allow black to fork his pawns and gain more access to his king side, while further hindering development that was going to be detrimental to him having any chance to mount any successful assult on black's king?

I clearly recall also saying that if you are going to castle opposite, you better have a plan to both attack and defend because of the position. That didn't mean he didn't have a chance, nor did I say he didn't. I also recall telling him to not trade, or allow his opponent to have access to his pieces to force trades.

I will admit that you very well probably do have a theoretical knowledge advantage for knowing the first mistake white made in this game. I don't play this opening, I don't like it. However,all of that aside, these two could probably make a few mistakes or innaccuracies (not blunders) against each other in the opening, but they aren't as crucial as they would be in the middle or end game. So from that stand point, you are splitting hairs and really just looking to put me down. If you really cared you would have privately discussed this with me, but you were more interested in making me look bad. You didn't really succeed though, you just think you did.

I have a feeling you wouldn't be so quick to run your "trap" if you didn't feel dignified by our rating difference.

I looked at the moves more carefully that you listed and it appears that two pawns and rook were going to be worth losing a bishop and a knight for, but white missed the good counter of black attacking a his rook with a bishop.

Yes, move 21 is bad, but the alternatives don't appear a lot better even after a few moves.The problem with allowing that knight to gain that position, was once it attacked the rook, whether the rook move, was used to defend the square to prevent the king/rook fork, then the knight would simply be moved to capture a pawn and fork both rooks.

Even if it is placed on d2, it will lose a pawn and allow black to keep the initiative. White's other rook will be under attack and the "knightmare" doesn't end there, especially after the bishop for knight exchange and then a rook check of the white king.

Suddenly, black has all but stripped away the king's protection and has the white rooks horribly out of sync and under threat of attack. It would be relatively easy to mobilize both of blacks rooks and gain firm control over the white queenside. 

It was pretty much elemetary, once the knight got into that position. My experience is, once your opponent gets his knight safetly to your side of the board on the 2nd or 3rd or 6th or 7th ranks respectively, where it can attack multiple pieces, especially if it has either squares to escape to, or any other piece guarding it's attacks, it is very bad news. It almost always results in material and or time loss and quite often it will become the integral part of your complete demise.

I meant explain the first position. Although thanks for explaining Bxb5 I did not notice he was going for a knight fork but failed to see the pin. As for the third yes it's lost at that point but losing a rook didn't help and general tips for seeing knight forks are still important if they help.

I was asking about the first position because you say that allowing Ng4 was the key mistake when to me it looks like a bad move because of f3. So I was wondering if I am missing something or since in general allowing a knight to get to close is dangerous and in this game it did in fact manage to cause problems you didn't look to carefully and in this case it is bad but something that should be watched out for in general.

It wasn't so much that allowing the knight to take the pawn on h2 loses the game directly. What I meant was, as an overall strategy, white needed to get his kingside pawns moving towards black's castled position to not only deter any encampments and losing territory, but those pawns are an awesome weapon in a storm against an enemy castle.

Considering white still needed to use two tempos to get his king out of harm's way(nearly inevitablely to come under attack), unless black suddenly played like a monkey, white needed to take the most viable option and quickly seize the initiative to have the best chance to win. If you compare the respective advantages for each sides' pawn chains, you'll see who ever waits around gets mauled.

In my mind, black gained superior position for a tactical battle, due to white's choice to castle queenside, but his positional chances were still alive with good play. Had he castled kingside, due to his central control and and his bishop untrapped, he could have had superior position.

I hope now what I am saying makes more sense.

White doesn't get two moves in a row. There were several other moves that keep everything safe. Sacrificing the Bishop for two pawns was just a terrible idea.

I think it was a fine idea to let black fork whites pawns on move 13, because they pawns aren't in danger after 14. f3, and black feels stupid for wasting a move and giving white a free one.

Also, the ideas of opposite side castling hardly apply here because the material on the board is so reduced. This was already said, but you didn't listen.

Just so you know, I don't even know what your rating is, but I could guess.

And once again someone is trying to apply the logic of best play that masters and up will make without fail, to people rated 1200-1300...now reevaluate the positions in the right context and stop trying to apply rules that aren't necessarily going to apply.

Sure Houdini will evalute it differently, but will they play it like Houdini would? Obviously not...so throw your theory out the window.

I am going to go on a bit of a rant now...

I am tired of players who are pretty good at tactics and who try to memorize every opening variation under the sun, and who worship Houdini 2.0....You guys don't get it do you?....You are as postionally and strategically ignorant as the program you use so much, to help you onto your pedistals...

Material evenly reduced is the key...so therefore it still applies when cross castling occurs... key things like initiative and tempos are crucial...or do I need to create a board with each side castled opposite with only three pawns and a king on the board on opposite sides to prove my point? This would represent even material. If they are in the same position but on opposite sides, who ever moves first has the advantage.

Now back to how it is wrong, when trying to apply what you seem to think is the most sound line, or the best tactical play, and you try to show someone one move(that you say it was the begining to the end for them on move 8, just an ex.), they probably won't remember the one subtle variation very well.

In fact the next time the same relative position is played, there is a really good chance that a completely different variation will get played, and the guy you spent all of that time on, trying to get to absorb your logic, won't even get to use it and might even forget it.

I instead, give them an overall view point for some strategic and positional ideas, instead of holding them to one particular move (like a hard line communist) and let them perhaps challenge conventional thinking and that of their opponent a bit, you might find they will learn a hell of a lot more from your posts.

They really don't know what to think of you guys after you confuse them, make feel dumb and then attack someone like me, because I refuse to cram college material down the throat of a middle schooler...because its proper theory...

If you don't like how I view chess and relating to other players....go ahead and take some varied guesses as to where you think I would tell you to stick it....or do you need a scientifically proven theory to make sure you understand?

14.f3 would have been good because Nf2 and Nxh2 won't work because the knight gets trapped. 14.f3 Nxh2? 15.Rh1! and Black loses a knight. Or,14.f3 Nf2? 15.Rd2! and the knight is trapped. So, the knight has to move back. 

20. Nc7 might have been good

Yep. And if you keep analyzing I think after 13...Ng4? 14.f3 Nf6?! black loses significant materal 15.e5 Nh5 16. Nd5 threatening both Nxc7 and g4

so that leaves 

13...Ng4? 14.f3 Nh6 15.Nd5 and white wins black's c pawn to go up a pawn with more space and more active pieces. White has a huge plus. 

you should have kingside castled so your king won`t be exposed

The last thing you want to do it trade your queen when you're up in development... I mean, that's the only way amateurs like us can push people around.

Instead of 9.Qxd4 (offering trade)

How about 9.cxd4 and a fine advantage: you have 5 pieces developed while black only one. On top of that you are one move from castling (black has to move knight to h6 to do so immediately) AND you have control of center.

Space. Center control. King saftey. Things always to keep in mind...

OMG.. move 50 killed it for u, instead of the king move, u should have started pushing the a pawn, that would have won u the game for sure ( one of the pawns would be promtoted. Im certain that would have worked

Your opponent is bad in opening and you gain the upper hand (have control the center, lead in development etc.) The problem I see here is you didn't take time to look at the opponent's threat. :)

It is hard to read tone but I think it is safe to say Qmar816 was being sarcastic. Although throwing the king's body to the vultures on move 50 unnecessary.