Next chess move - how to analyze chess position

Take a look at this position. White to move. How would you evaluate it? What is the best move?
Interesting position number 1
Latest version of the strongest chess engine in the world - Stockfish at depth 28 show +1.4 score and suggest Qd4 for the next move. But do you agree with it?
Wrong best move by Stockfish
Are you ready to get surprised?

Here is the magic move - Qh8+ and mate in 8. Note how chess engine change its mind immediately after move was done.
Magic chess move
No, it doesn't mean that Stockfish is weak. It also doesn't mean that engines are bad at calculation. The point is you should not rely on programs entirely. Don't forget about good old brain.

Here are 2 more interesting positions. At the position №1 engine shows -1.7 score at Depth = 22. At the position №2 score = 0 (Stockfish think that it is a dead draw at Depth = 22). In both cases evaluation is incorrect.

White to move on both puzzles. Find the best move. Answer is on the bottom of this page.
Interesting position number 2
Interesting position number 3
Position №1
Position №2
FEN: 8/PBn5/5k2/7p/5p2/7p/3K4/8 w - - 0 1
FEN: 4rb2/1p1q1ppk/p1n1p2p/2p1Pn2/3PNR2/2P2K2/P2QBP2/6R1 w - - 0 1
FEN: r5k1/p1p1K2p/1p5p/1N6/4P1PB/3P1b2/P1P2p2/Q3q3 w - - 0 1
Tools for position analysis


There are special programs to analyze games and positions - chess engines. Typically, these programs are console applications without an interface. Therefore, in addition to the engine itself, you still need a GUI (graphic user interface). Here are a few variants you can try:

1. Online analysis board at lichess. It is convenient
and free.
2. Arena GUI with the Stockfish chess engine. Powerful and free.

First variant is simple. You don't need to download anything. Just open the link and use it. Don't forget to enable chess engine (turn on slider in the top-right corner (see picture):
online lichess analysis board
Also you can enable up to 5 best moves and 5 lines (principal variations) in the analysis options. There are a few other parameters, which you can configure on this panel. Press button in the bottom-right corner to open it.
analysis parameters
Second variant is a bit more complicated (however, it gives you more possibilities - for example, you can use any engine you want, which sometimes very useful in position analysis). You need to download program called Arena Chess GUI and install it on you computer.

Also you'll need chess engine. Use your favourite or download one of the recommended here.

Example - position analysis in the Arena Chess GUI 3 with the classic Rybka 2.3.2a engine:
Arena GUI
FEN and PGN


You can set up specific position in a different ways:

1.
Setup position manually
via drag'n'drop. At lichess you can do it here. Also we have own chess calculator at our website, where you can manually construct position and see next best move.

2.
Load FEN of the position
. FEN (Forsyth-Edwards Notation) is a standard notation for describing a particular board position of a chess game. Here is FEN string for the start position:
rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR w KQkq - 0 1
You can load FEN both at online lichess board and in the Arena GUI. Other GUIs and online calculators also usually support these format.

3.
Load PGN of the position
. Portable Game Notation (PGN) is a plain text computer-processible format for recording chess games (both the moves and related data), supported by many chess programs.

Here is PGN example - one of the famous game of the Mikhail Tal against Vasiliy Smyslov:

[Event "Bled-Zagreb-Belgrade Candidates"]
[EventDate "1959.09.07"]
[Round "8"]
[Result "1-0"]
[White "Mikhail Tal"]
[Black "Vasily Smyslov"]

1.e4 c6 2.d3 d5 3.Nd2 e5 4.Ngf3 Nd7 5.d4 dxe4 6.Nxe4 exd4
7.Qxd4 Ngf6 8.Bg5 Be7 9.O-O-O O-O 10.Nd6 Qa5 11.Bc4 b5 12.Bd2
Qa6 13.Nf5 Bd8 14.Qh4 bxc4 15.Qg5 Nh5 16.Nh6+ Kh8 17.Qxh5 Qxa2
18.Bc3 Nf6 19.Qxf7 Qa1+ 20.Kd2 Rxf7 21.Nxf7+ Kg8 22.Rxa1 Kxf7
23.Ne5+ Ke6 24.Nxc6 Ne4+ 25.Ke3 Bb6+ 26.Bd4 1-0

Try to copy this PGN and paste it at lichess here. Now you can analyse great game of the grandmasters with the engine and convenient board!
Tal super move
Answers to puzzles.

Position 1 - Rxf5 exf5 Qxh6+ and mate in 5

Position 2 - 1. Kd3 h2 2. Kc4 Kf7 3. Kc5 Ke6 4. Kb6 Kd7 5. Bh1 Kd8 6. Bb7 Kd7 7. Bf3 ... and here engine finally jump from the score = 0 and shows +9.7 for white.
FEN and PGN


You can set up specific position in a different ways:

1.
Setup position manually
via drag'n'drop. At lichess you can do it here. Also we have own chess calculator at our website, where you can manually construct position and see next best move.

2.
Load FEN of the position
. FEN (Forsyth-Edwards Notation) is a standard notation for describing a particular board position of a chess game.

You can load FEN both at online lichess board and in the Arena GUI. Other GUIs and online calculators also usually support these format.

3.
Load PGN of the position
. Portable Game Notation (PGN) is a plain text computer-processible format for recording chess games (both the moves and related data), supported by many chess programs.

Here is PGN example - one of the famous game of the Mikhail Tal against Vasiliy Smyslov:

[Event "Bled-Zagreb-Belgrade Candidates"]
[EventDate "1959.09.07"]
[Round "8"]
[Result "1-0"]
[White "Mikhail Tal"]
[Black "Vasily Smyslov"]

1.e4 c6 2.d3 d5 3.Nd2 e5 4.Ngf3 Nd7 5.d4 dxe4 6.Nxe4 exd4
7.Qxd4 Ngf6 8.Bg5 Be7 9.O-O-O O-O 10.Nd6 Qa5 11.Bc4 b5 12.Bd2
Qa6 13.Nf5 Bd8 14.Qh4 bxc4 15.Qg5 Nh5 16.Nh6+ Kh8 17.Qxh5 Qxa2
18.Bc3 Nf6 19.Qxf7 Qa1+ 20.Kd2 Rxf7 21.Nxf7+ Kg8 22.Rxa1 Kxf7
23.Ne5+ Ke6 24.Nxc6 Ne4+ 25.Ke3 Bb6+ 26.Bd4 1-0

Try to copy this PGN and paste it at lichess here. Now you can analyse great game of the grandmasters with the engine and convenient board!
Update [22 Feb 2021]

Here is one more interesting position. Black to play.
FEN: 1r3rk1/p4pb1/3pp2p/2n1n2q/4PBp1/1NN1Q3/PPP2PP1/3R1RK1 b - - 0 1

Chess engine (Stockfish 13 and older versions) shows +- equal score for the position. However, there is a continuation, which leads black to win. Check the study below (you can press arrows left and right to navigate through the moves).
chess cheat bot
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