Puzzle solving - Thinking process explained

I found out that I learn the most when I fail to solve a puzzle. Then I start to analyze the puzzle with an engine to see where my thinking process was wrong or incomplete.

I played this puzzle a few days ago and failed to solve it, because I made a few simple mistakes.
Lichess puzzle: lichess.org/training/66176 / Current rating 2526
I recommend that you try to solve it first, before you read what I thought while I tried to solve this puzzle.
Write down your thoughts which you had while you tried to find move 1, 2 and 3 for white. Than compare this to my thinking process.


move 1.
- I checked the material on the board. White is already two pawns up.
- I checked the weaknesses and strenghts for both sides
+ The black knight on c4 is hanging and white can take it with Bxc4
+ White is not very well developed / Black is very well developed
+ White's king is still in the center and not very safe
+ Here I made my first mistake ! I never checked whether black's king is safe. This is important on move 3
- I checked the canditate moves for white. Here I only saw Bxc4
- I tried to find out what black would play next. Here I saw that Black would most propably play Qxe4+ and then Qxg2. The move Qxg2 would come with an attack on the unprotected rook on h1.
- Therefore I already tried to figure out how I could protect this rook and found the line
1. Bxc4 Qe4 2. Qe2 Qxg2 3. Qf3 . I was pretty sure that this line would win for white.
- Then I played the move Bxc4 and black took on e4 with his queen, which leads to the next diagram.


move 2:
- I had already planned to play Qe2 while I was thinking about move 1.
- But here I stopped for a moment and tried to calculate whether the moves Be2 or maybe Ne2 would be maybe better
- I decided that Qe2 with the plan to play Qf3 would still be the best plan. So I played it.
- Black took now on g2 with his queen as expected, which leads to the next diagram


move 3:
- And here comes now my stupid mistake. I simply played Qf3 within one second and failed to solve this puzzle.
What has happened ?
- I didn't check the position after move 2, because I had already convinced myself all the time that Qf3 is the best move.
- If I had checked the position carefully, I would have seen clearly that Qg4+ is a much better move. This forces the trade of queens which reduces the attacking changes for black dramatically.

What did I learn after this failure ?
- Don't stick to plans which you have made a few moves before !
- After each move there is a new puzzle on the board. Always start a new thinking process !
- King savety : I never checked the savety of the black king. Not on move 1 and definitely not on move 3. On move 3, it is quite obvious that white can give a check on g4. But I didn't search for checks.

It seems that sometimes bad habits return when I play puzzles.
The puzzle which I want to show here is a good example for a phenomon which I gave now the name "tunnel vision".
I looked on the board and saw only 25 squares (d4 to h8).
White to play !!

I saw 2 variations which win both the black queen.
1. Ng6+ Kh7 2. Ne5+ Kh8/Kg8 3. Nxf7
2. Ng6 Kg8 2. Bd5 (pinning the queen) Qxd5 3. Ne7+ Kh8(kh7) 4. Nxd5
(Note:I knew the pattern of the second variation from a puzzle like this one. lichess.org/training/86489 )

Now play this puzzle and try to avoid the "tunnel vision".
Lichess puzzle : lichess.org/training/67232 / Current rating 2376

Checklist for puzzle solving.
General rules, which are of course also applicable for a normal chess game.
1. Count the material on the board. This will give you a clear indication which goal you have to achieve.
2. Identify all weaknesses of your opponent (king safety and king mobility, hanging pieces, loose pieces, semi-loose pieces, trapped pieces, overworked pieces, weak backrank ...)
- hanging piece = a piece which has more attackers than defenders
- loose piece = a piece which has no attackers or defenders
- semi-loose piece = a piece which has the same number of attackers and defenders
- a trapped piece = a piece with restricted mobility
- overworked piece = a piece which has too many duties at the same time (=Such pieces are restricted in their mobility)
(Piece = king, queen, rook, bishop, knight and pawn !)
If you attack your opponents king, then also empty squares can be "hanging", "loose" or "semi-loose".
3. Identify all weaknesses in your own position
4. Identify all potential tactics in a position for you and for your opponent (pins, double-attacks, forks, x-ray attacks, checks ...)
If a tactic doesn't work in the starting position, think about ways to make it work ! Deflecting your opponents pieces is very often the solution.
5. Identify all of your candidate moves. Start with checks (also checks which involve a sacrifice) and captures, because these moves are the most forcing moves. Then look at potential tactics.
6. Identify all possible candidate moves of your opponent. Avoid wishful thinking. Look at the strong forcing moves, not at the weak moves which make your combination work.
Turn the board around and try to look at the position from the perspective of your opponent. Find the most annoying moves. Checks, sacrifices and desperado moves ! Look for possible perpetual checks.
7. Calculate all lines and all candidate moves until the end. If you found 2 candidate moves, don't play move 2 after you found a refutation for move 1. Sometimes you will also find a refutation for move 2. Then you know that there is maybe a candidate move no. 3, which you totally missed.
8. If you see a good move, always look for a better one.
9. Keep in mind, that after each move there is a new puzzle on the board. Start your calculation new.
10. Don't make impulsive moves ! Calculate first.
11. When does a tactic end ? A tactic ends in that moment when there are no more checks, captures or any other threats in the position left.
If you stop with your calculation too early, then you will sometimes win material and then you get checkmated. LOL.

There is a mistake which all puzzle solvers make all the time. They don't see all possible canditate moves or they exclude possible canditate moves from their calculation because they think that a certain move doesn't make any sense at all. Allways keep in mind that under certain circumstances all moves can make sense. Maybe not at first sight, but after 2 or 3 more moves the situation on the board could have changed significantly.
Exercise:
1. Identify all candidate moves (all checks and captures) for white
2. Calculate all candidate moves for white until you see it is winning or losing
Lichess puzzle: lichess.org/training/68747 / Current rating 1988
White to play !!

My thoughts were the following when I calculated this puzzle:
Possible canditate moves for white are:
- All possible checks !
1. Qh8+ (It seems that this move loses the queen for nothing)
2. Qh7+ (It seems that this move loses the queen for nothing)
3. Qxd8+ (seems to lose the queen for one rook ?)
- All possible captures !
4. Qxd4 (maybe correct, calculate !)
5. Rxd4 (looks stupid, Black can take the rook on c1 with check. Calculate at the end)
6. Nxd4 (maybe correct, calculate !)
7. Rxc8 (leaves the rook on d1 unprotected. Loses after Nxf3. Calculate to be sure.)

P.S.
1. I didn't mention black's weaknesses by intention. This is normally the second step which you have to do. Figure out the weaknesses for both sides !!
2. And of course, the first step is to count the material on the board !

Very interesting elements !

One i may add, that sometimes made me miss a winning line, is pieces values as explained here www.chess.com/article/view/chess-piece-value

For example, in some puzzles you're expected :
- to trade rook against at least 2 pieces among opponent's bishops/knights (or better) ; aka 5 < 6+
- to trade queen against at least 1 opponent's rook plus 2 pieces bishops/knights (or 2 rooks) ; aka 9 < 10+

Otherwise the trade is lost and you fail solving puzzle !