Learning WHY a move is a mistake/blunder

Edited:  I created my account a couple of years ago, but have just started actually playing and trying to learn. I've used the tutorials and now play against the easier "adaptive" computer opponent to get my bearings. I'm really impressed with the site, especially what I'm currently able to access on the "free" tier. 

One of the things I'm struggling with when I review games vs the computer afterward is understanding WHY a move was a blunder or mistake. The analysis will show me the move I made, the move that it says I should have made, but the descriptive text doesn't help me know WHY the suggested move is better (just says "black is winning" or similar).

In the earlier parts of the game when the next move isn't as obvious (to me) as it becomes later in the game, I don't often follow why one move is preferred over the other.  Does the site/app have a way (possibly paid tier?) to see the why the guidance is what it is?

Lets use an example from one of your games.  Look at the position after your last move (Blunder) and try and figure out on your own why its a blunder.  If you cant then click on the "Analysis" tab on your games.  Hope this helps.

Opening Principles:

1. Control the center squares – d4-e4-d5-e5.
2. Develop your minor pieces toward the center – piece activity is the key. Centralized piece control more squares.
3. (King Safety)
4. Connect your rooks. There should be no pieces between your Rooks.

The objective of development is about improving the value of your pieces by increasing the importance of their roles (Piece Activity).  Well-developed pieces have more fire-power than undeveloped pieces and they do more in helping you gain control.

Now we will look at 5 practical things you can do to help you achieve your development objective.

They are:

1. Give priority to your least active pieces.

• Which piece needs to be developed (which piece is the least active)?
• Where should it go (where can its role be maximized)?

2. Exchange your least active pieces for your opponent’s active pieces.
3. Restrict the development of your opponent’s pieces.
4. Neutralize your opponent’s best piece.
5. Secure strong squares for your pieces.

Don’t help your opponent develop.

There are 2 common mistakes whereby you will simply be helping your opponent to develop:

1. Making a weak threat that can easily be blocked
2. Making an exchange that helps your opponent to develop a piece

Pre Move Checklist:

1. Make sure all your pieces are safe.
2. Look for forcing move: Checks, captures, threats. You want to look at ALL forcing moves (even the bad ones) this will force you look at, and see the entire board.
3. If there are no forcing moves, you then want to remove any of your opponent’s pieces from your side of the board.
4. If your opponent doesn’t have any of his pieces on your side of the board, then you want to improve the position of your least active piece.
5. After each move by your opponent, ask yourself: "What is my opponent trying to do?"

This is very helpful, thank you, especially the checklist. Using your checklist, it looks like:

1. Pawns at c3 and f2 are not safe.

2. For forcing moves, no check options and Qxe4 (think that's right) is a capture that was available, but then I've traded my queen for that knight. Another pending threat is the knight at c6 could move to b4 and threaten my queen.

3. The only black on my side of the board is the knight at e4 and only the queen can capture it in this move. I could move the other knight to d2, but that would probably trade knight for knight after a move or two?

I clicked on the analysis and it looks like the computer recommended h4 for me at that point. 

So moving my knight to g5 was a blunder (it was captured on black's next move), though still not sure I know why the h4 pawn move is "best" at that point (at least relative to other moves that could have been made and still been safer than the knight to g5 was).

Obviously, I have a lot more of the lessons/tutorials to go through and blunders/mistakes to make... I guess the main issue leading to my post was seeing what was good/bad but (aside from the obvious stuff) not understanding yet why it's good or bad. I'll keep going on the tutorials/lessons — and again, really appreciate your time!

Just to followup... my reply above was started pretty quickly after your first, so I hadn't seen the second message — which is even more amazing, thanks. There's a lot for me to dig into there to help me get past just thinking move-for-move.

Chess like anything in life that we want to learn about takes time.  Have fun, and always ask questions.  Chess is a game that requires you to turn back into a 2 year old.  Everything should be "Why?"

Everything IMBacon said is true, and his list of principles are valuable for any beginning player--and not just beginners! But as important as principles are, they are not enough. Often nothing takes the place of taking a good look at the board and thinking, "I I go here, he can go there." To improve at chess, you have to look and you have to count.  Before playing 6.Ng5 you needed to look at the board and you need to count how many times your Ng5 will be attacked and how many times it will be defended. If you do this consistently, you will avoid a lot of blunders, and you will start playing "real" chess

If you need help improving, I have several tips for you. You can read them here:

https://www.chess.com/blog/nklristic/the-beginners-tale-first-steps-to-chess-improvement

knight has 1 defender and 2 attackers

"Often nothing takes the place of taking a good look at the board and thinking, "I I go here, he can go there." To improve at chess, you have to look and you have to count."

I'm not aware of a computer that can explain all the principles to a move failing in a given position. What it can do is show you lines, which you can explore. Try and see why certain responses would be bad for you, as long as your opponent has at least 1 good reply that puts you in a worse spot than another move would leave you in, that's a worse spot. 

Analyze the board state yourself, use the resources available to you to break it down, and don't forget you can ask people for thoughts.

Take the position Bacon found. It wasn't just moving your knight twice. Your opponent can just take your knight with their knight, and what are you doing to do? You're down a piece. Now, normally you being able to recapture with your bishop could get you back the material, but now they just take that with their queen. So you killed their knight, they killed your knight and bishop. That's not a good exchange for you.

maybe dumb question, but the "defender" means someone who could take out an attacker.. so acts as maybe a deterrent to attack? For example, the defender in this example is the bishop? Does the piece value matter? For example, the Queen attack seems very unwise, because the bishop defend? So isn't it really only 1 attacker? I guess it seems the bishop is fairly effective defending against both attackers?

It matters. They can't take with the queen the first time because of the bishop, even if the knight took back, the queen is worth more than the knight and bishop lost. But the knight does not care. It can take, and the queen is like a back-up attacker. 

A knight and a bishop is worth more than a knight, and a knight is worth more than nothing. Those are the two exchange options for white if black takes. 

Thanks all, there's lots of good advice in here with lots to read (and re-read) and practice. 

One of the main things I realize here is that the computer can tell me better/best moves (based on math/data)... and how suboptimal other choices are in comparison. It's just not going to be able to tell me (as a beginner) "your move was a mistake because your opponent can do X, which puts you in position Y, which hurts you later when Z happens " (or similar plain-English beginner explanation). 

I will continue with the lessons, articles, videos... and keep playing!

Fantastic notes. 

Yes piece value matters. It's certainly very important in figuring out in which order you capture! But to make things clear, after you played 6.Ng5, that knight is attacked by Black's Ne4 and Qd8, two attackers. The Ng5 is defended by the Bf5--one defender. So 6...Nxg5 7.Bxg5 Qxg5 leaves you a piece down for nothing. That's what I meant by counting. I hope that helps

This is outstanding stuff. I'm glad I found it! 👊

I also started playing recently, and I'm having the same trouble. But not on situations like your example. It's clear to me that you're  essentially just losing a knight (or losing a knight and a bishop for his knight)..   But that's clear to me, especially in hindsight. Most times I make a mistake or blunder, I can usually understand why when I look at the analysis. It's usually fairly obvious. Sometimes it takes me a minute.

Here is an example:

When I first glanced at this, I wasn't sure why this was the suggested move. But after playing it out in my head, I realized that if my opponent took my knight, I was going to be able to win his rook. I of course didn't see this while playing (especially rapid) but figured out the logic behind it. And hopefully if this situation comes up in a game again, I will recognize it and not make the same mistake twice.

But every once in a while there is a move I make (or rather one I didn't make) that I can't really figure out what's the rationale behind it.  I can't think of a good example off the top of my head though.. But a minor example is there have been times where I was playing Ruy Lopez and my opponent plays A6. I usually will go back with my bishop. But there have been different games where I've gone back in one game, and just taken the knight in others. And I've had the engine tell me both were mistakes at different times. They were obviously at different points in the game but I couldn't figure out what the variable was in the position that made each move a mistake at the time.

I've gotten a lot better in the few months I've been playing and I am actively trying to improve but it's hard to learn from mistakes when you don't always know why they are mistakes.

Any advice on top of what you already said for examples that aren't so obvious like the OPs knight move? Because just studying engines and memorizing moves doesn't seem optimal and even if I did... If I don't know why it's a mistake then I likely wouldn't be able to tell from the position if the "correct" move would even be so in that spot..

Any further suggestions would be appreciated! 👍