Friday, April 19, 2024


 The problem set I use is based on a few simple conditions:

  • two movers
  • not mate
  • rating about 1700

Despite these straightforward choices, the set is quite diverse. Often it is questionable why it are two movers, since a lot of interesting follow up moves are left out for no apparent reason.

Besides that, the end isn't always about gaining wood, as I was inclined to think. Sometimes it is about promotion, or a winning endgame, or an invasion. I gave these problems their own tag, so I can have a deeper look at them later on.

I have seen most problems about 30 times, which gave me the possibility to write a narrative for each of them. I have been surprised how rich these simple looking problems turned out to be.

Of the 111 problems, 11 got an extra tag "invasion" by me. I'm especially interested in that, because the study of the Art of Attack in Chess by Vukovic showed the importance of that idea. Vukovic made a starting point with his book. It is a pity that nobody has picked up the gauntlet he threw at us.

The Art of Attack in Chess lays an emphasis on the lines of attack that end at or near the opposing King. There is a gap in chess knowledge between the opening and the attack of the King. Between the opening and the attack lies the LoA landscape. That landscape is formed by the pawns and the piece placement.

In the past year I had a closer look at this area. Especially CM Can Kabadayi has written a few books for Chessable that prove to be useful.

The elements of interest are:

  • Activate your pieces
  • Bury the pieces of your opponents
  • Which pieces to exchange

The role of the pawns can be quite ambiguous. Hence it is very difficult to define rules for them. The pawns are important because they move slow and can only move in one direction. That is the reason why they are at the base of any plan.

  • They form the lanes for the pieces, the LoA landscape
  • They can activitate your pieces by opening lines and diagonals
  • They can bury your opponents pieces
  • When fixed, they decide which pieces are bad and which are good
  • When mobilized, they can act as a wedge
  • They can claim space
  • They can become targets themselves
  • They can determine the outcome of an endgame
  • They can protect your king
  • They can act as a crowbar
Rules for pawns without a good grasp of the context turn out to become counter productive. And there are quite an amount of different contexts. Yet their specific properties (slow and unidirectional) are so important that we must study them.

But beware of the context! The context is now invasion.

White to move

r3r2k/1p5p/p1p2q2/3p1Nn1/1P6/P2Q2R1/2P3PP/5R1K w - - 0 1

There are three moves that are winning. Why are the pawns so important? Because they aren't there where they are needed. Can you describe the LoA landscape?

UPDATE part 1
Let me first put a few things straight. I never was very fond of the PoPLoAFun system. It emerged from the analysis of tactical problems, but it never felt universally applicable to every type of tactics problem. If you look at the previous post for instance, the tactic is best described by a concrete chain of logic.
When I studied the Art of Attack in Chess though, the PoPLoAFun system seemed perfectly suited to describe the no men's land between the opening and the attack on the king. When there is no concrete tactic yet, but the pressure is already building up. The LoA's (lines of attack) provide a handle for interrogating the position. For practical reasons I limit the scope of a LoA a bit:
  • a LoA starts with an attacker and ends with the opponent's King, or at a square next to the King
  • There is no need to stretch the LoA to the edge of the board. For me that complicates matters for no reason. The square behind the King is far enough, when applicable
  • Concrete tactics are best described by a logical narrative
  • A LoA is neutral by its very nature. It is a mere pathway. This means that sometimes a battle for domination will take place
  • The squares that makes the LoA change from direction are pivotal squares
  • A pivotal square that lies in the enemy camp is an invasion square
  • For the squares around the King I will use the PoP (point of pressure) or the focal point (coined by Vukovic)

Description of the LoA's


  • attacker Rg3
  • blocked by black Knight
  • Knight is B.A.D. (Barely Adequate Defended)
  • potential defenders K, Q, R, h7
  • focal point g8


  • attacker Rf1
  • bonus target Qf6
  • invasion square f8
  • potential defenders Q, R
  • battle for domination
  • Rf1 is B.A.D. (Barely Adequate Defended)

a1/h8 diagonal

  • attacker Qd3
  • defenders Q, R
  • battle for domination
  • target K
  • a1 = B.A.D. (Barely Adequate Defended)

Knight jump d6-f7

  • attacker Knight
  • defenders Q, N
  • targets R, K
  • discovered attack Nd6
  • knight fork f7


  • dominated by black Re8
  • target Kh1
  • invasion square e1

Intersection c3/h8 diagonal with g-file makes g7 a focal point

Intersection c3/h8 diagonal with e-file makes e5 a PoP (point of pressure)

UPDATE part 2

Let me recap. The first action of the eagle is to get an overview of the position:

  • status of the targets (B.A.D. (Barely Adequate Defended), LPDO)
  • status of the defenders (Fun)
  • status of the LoA's (PoPs, invasion, pivotal, blockaders, clearance)
  • immanent tactics (discovered attack, pin, fork)
That is seeing every salient cue in the position. This is a task that belongs to system 1, the eagle. The second step is to use your logic, in order to reveal the hidden features of the position. System 1 and system 2 work together in a cyclic process. Neither the frequency nor the order in the cyclic process is important.
Once all salient AND hidden features are known, it is time to build a logical narrative. Which is as sequential as possible, with a clear beginning, order and end.

When I looked for the status of the LoA's, I completely missed the knight jumps and the diagonal c3/h8.

While fiddling around with the Knight, I asked myself, what is the difference between 1.Ne3 and 1.Nh4? The first move is winning while the second is equal. Why? That revealed that the knight blocks a counter attack along the e-file when placed on e3.

1.Nd6 is a discovered attack against Q and R. Fiddling around showed what happens when the black Queen takes the knight. The black Queen is overloaded. When the black Queen doesn't take the knight on d6, the knight fork on f7 starts to wink. The black knight on g5 and the black king are on a knight fork's distance.


  • Seeing salient cues
  • Revealing hidden cues by logic
  • Stitching everything together in a logical narrative


  1. I believe someone picked up the gauntlet.Jacob Aagaard Volume 1 and 2 are a modern Art of Attack. One could spend the next five years in these books.

  2. Check out this book on Goodreads: Attacking Manual Volume 1

  3. Sorry about the excessive posts. I am the Jim with picture of John Lennon in goodreads

  4. Temposchlucker asks:

    "Can you describe the LoA landscape?"

    There are four important LoA for White:

    1. f1 <-> f8
    2. a1 <-> h8
    3. g1 <-> g8
    4. a1 <-> h1 (defensively)

    There are four important LoA for Black:

    1. a8 <-> h8
    2. h8 <-> a1
    3. d8 <-> h4
    4. f8 <-> f1

    Note the indirect "clash" centered around the LoA a1 <-> h8. Black needs to defend it; White needs to open it for attack on the Black King.

    The WRf1 is B.A.D.
    The BNg4 is B.A.D.

    The Black King is more exposed than the White King, but both Kings are vulnerable (for the moment) to a back rank mate.

    The Black Queen is overloaded: it must “protect” BNg5 and the diagonal h8 ↔ a1. It is vulnerable to attack from the WRf1 which can be “discovered” by moving the White Knight.

    The BRa1 is doing nothing for the Black King’s defense and MAY become vulnerable to a tactic (fork of LPDO and King) on the back rank IFF the BRe8 moves away from the mutual defense between the two Black Rooks. Ergo, White has a temporary superiority [attackers versus defenders] on the kingside.

    FWIW, I “SAW” two of the three good initial moves for White; the third (moving away from the general direction of the Black King and Black Queen) totally escaped my attention.

  5. I hope to find time tomorrow to work out more details and add it to the post. For now let me say that you totally missed one line of attack for white.

  6. PART I:

    For a long time, my middle game study revolved around Nimzovich’s My System and was almost exclusively focused on the static features covered in the first Part of his book. For the past few years, I have switched to studying more dynamics than statics. It is my opinion that the current style of play is very dynamic, and thus there is considerably more emphasis on tactical issues in all stages of the game. Perhaps there are now sufficient resources to formulate a more generalized approach to all aspects of the middle game.

    Takchess wrote an excellent review of GM Aagaard’s Attacking Manual Volume 1 on Goodreads:


    GM Aagaard, in his later book Grandmaster Preparation: Thinking INSIDE The Box [which summarizes the Grandmaster Preparation series of workbooks], added an eighth broad principle of dynamic strategy to those previously detailed in Attacking Manual Volume 1.

    The eight broad dynamic strategical principles [emphasis added] are:

    1: Include ALL the pieces in the attack.
    “Local superiority is what it is all about.”
    “Include the last piece. Include as many pieces in the attack as you can WITHOUT LOSING YOUR MOMENTUM.”

    2: Momentum
    “Steinitz: When a sufficient advantage has been obtained, a player MUST ATTACK or the advantage will be dissipated.
    “Once you have improved your position to the maximum, YOU MUST EXECUTE YOUR ATTACK WITH THE GREATEST POSSIBLE PACE.”
    “A lead in development should be exploited at its zenith.”

    3: Colour
    “Most chess pieces are colour blind!”
    “Controlling one colour of squares is one of the main indications [“CLUE!”] of a promising attack.”

    4: Quantity beats Quality
    “A piece can only attack a square ONCE, no matter its alleged exchange value in pawns.” [Corollary: A piece/pawn occupying a square CANNOT attack/control that square. Think about the Classical idea of “occupying center squares with pawns.”]

    5: Attack the WEAKEST square.
    “You should strike at the weakest spot in the opponent’s position.”

    6: Attack the STRONGEST square.
    “Strike at a square that the opponent has overprotected, in order to ruin his coordination and get through to the real weakness.”

    7: Evolution/Revolution
    “Get a good feeling for the attacking flow: prepare the forces as much as you can, do with them what you can, and then the position will change, usually in a big way.”
    “Regroup before proving compensation.”

    8: The Killzone
    A mating attack is likely to happen in a limited area of the board. If the opponent’s king manages to escape this area, the attack is likely to fail.

  7. PART II:

    These dynamic principles supplement the Classical strategic principles articulated by Steinitz and elaborated on (with additions) by Lasker in his book Lasker’s Manual of Chess. GM Euwe in his two-volume opus Het Middenspel [The Middle Game], Book Two: Dynamic and Subjective Features covered the following dynamic aspects in detail:

    PART VI. The Initiative
    23: The Activity of the Pieces
    24: The Security of the King
    25: To Make the Exchange or Permit the Exchange?
    26: The Avoidance of Exchanges

    PART VII. Attacking The King
    27: Attack against the King Castled King Side
    28: Attack against the King Castled Queen Side
    29: Attack against the Uncastled King

    PART VIII. The Art Of Defense
    30: Wilhelm Steinitz as Defender
    31: Emanuel Lasker as Defender
    32: Defense in General

    PART IX. The Technique Of Manœuvring
    33: Typical Manœuvring
    34: How Tarrasch used to Manœuvre
    35: Lasker’s Manœuvring Skill
    36: The Teachings of Nimzovitch
    37: Capablanca Manœuvred only when Necessary
    38: Alekhine’s Dynamic Manœuvring
    39: Indian Style Manœuvres: Sultan Kahn
    40: Games of Manœuvre from Recent Times

    PART X. Liquidation
    41: Liquidation in the Opening
    42: Liquidation for Defensive Reasons
    43: Liquidation to Preserve an Advantage
    44: Combinative Liquidation

    PART XI. Familiar Failings
    45: Eagerness to Win Material
    46: Eagerness to Exchange Pieces
    47: Eagerness to Checkmate
    48: Obsession with the Draw

    PART XII. Personal Style
    Twenty-eight Strong Masters

  8. Spent a few hours while on a commercial. Flight looking at this position my analysis to follow tomorrow.

  9. After a couple of failed attempts leaving my contents by my phone, I have moved to a laptop.

    Intial Position Analysis

    Material Count

    Even up 5 pawns, 1 Knight N , 1 Queen and 2 Rooks. Both are castled Kingside . Black has a Queenside majority of pawns 4 vs 3 pawns.

    Strength vs Weakness.
    Black Rooks support each other but arent active. Unlikely to be an 8th row mate for white. Neither side have forward pawns that are likely in the short term to promote . Queen is loose for Black. Knight is protected by Queen which can lead to entrapment.
    H7 is aligned with the Queen but Unlikely to get enoght tempos to get white rooks into action. At present there is a discover attack on the queen with any knight move and that the rook and capture blacks Knight. A discovered attack by Ne6 (rook attacking Queen and kNight attacking rook seems possible due to queen entrapment on the long diagonal Note N & K present position and suspectible to a Knoight fork from f7 . Also the classic mate of Knight f7 and rook on g file would be mate. Also looked at kicking the N with an h pawn. white has some back rank issues give the queen some duties that may be relinquished with some tempo In one line the checking queen cant be capture due to whites N blocking the black queens rays is she caputured the rook.

    Blacks King is not well protected thoughts are 7th file mate on H7 with a future h file rook or perhaps arabian knight mate supporting the mate. The a1 H8 diagonal is extremely weak and if the queen is lured off the diagonal she can be entrapped even on the g7 square (whites queen supported by Knight in present position. This duty makes the knight and other squares free for white.

    That's what I got will let you know if I forgot any thoughts in this post.


  10. As I mentioned previously on another post I recently mentioned that I was interested in pulling a piece of a square where if it remained would prevent a tactic . With a check it is forced to return. I struggled as to why this is so . I now think it because if it was intially there it would use it's tempo to take the attacker. By having moved from the square it has to use its tempo to return ....Something that I had a blind spot.

    Here are some other things I calculated an initial pin by 1. Qd4 . also 1.Nd4 and 1Ne3 and 1. Nh6 and 1.Rxg5. I forgot which line but I thought was negated by ... Re5 in front of a Queen on D6 . I think this rook sould of simply be captured the queen x queen was open to a royal fork by white.

    And yes f7 is absolutely an invasion square .

  11. You might find this game interesting as to the ever changing invasion squares and mating attacks. It starts getting interesting at move 16. From early game in Art of Attack Volume 2 which is more about Tactics Volume 1 is about general rules of attack.

  12. Of course from attacking Manual not art of attack....

  13. PART I:

    This morning, I took another look at the "solution" to the problem as proposed by Chess Tempo. (I have no idea what engine was used to create the solution.)

    0...Kh8 1.Nd6
    + +5.83 1. Nd6
    + TRY AGAIN +2.52 1. Rxg5
    + TRY AGAIN +2.12 1. Ne3
    + +0.41 1. Kg1
    + +0.22 1. Nd4

    + -5.78 1... Re1
    + -7.48 1... Qxd6
    + -7.76 1... Nf3
    + -9.30 1... Re3
    + -13.25 1... Qg6

    + +6.27 2. Rxe1
    + TRY AGAIN +2.13 2. Nf7+
    + -0.54 2. Rg1
    + -2.93 2. Nf5
    + -3.26 2. Kg1

    Obviously, the breadth of the analysis was set at 5 alternatives. There is a significant difference between the “best” move [1. Nd6] and the next two alternatives [1. Rxg5 and 1. Ne3]. The final two alternatives [1. Kg1 and 1. Nd4] would not make my cutoff for candidate moves. Not because of the poor relative score (which I did not see until after determining the first two moves, playing what I considered to be the better move [1. Nd6] and learning that I had chosen the “correct” solution), but because they don’t seem to meet the requirements of the position. White has significant tactical shots and superior assets in the vicinity of the Black King. Recall GM Aagaard’s 2nd principle regarding Momentum: “Once you have improved your position to the maximum, YOU MUST EXECUTE YOUR ATTACK WITH THE GREATEST POSSIBLE PACE.

    My uninformed question is simple:

    Why would any moves beyond those first three alternatives be considered as candidate moves?

    It seems difficult (to ME) to justify investigating alternatives beyond what can be rationally SEEn as the strongest alternatives from a human perspective. If the overall objective is improving skill over-the-board, I fail to SEE how exploring arbitrary inferior alternatives improves skill.

    It is the same problem I have with super-accurate valuations based on the scale of values (hundredths of a point) proposed by GM Larry Kaufman. Centi-pawn evaluations are fine for computer analysis but, absent knowing and understanding all of the scoring functions involved, are worse than useless for humans. We can’t calculate to that level of distinction even if we tried. Even the Reinfeld relative valuations based on a pawn being equal to 1 are problematic: are 9 pawns equal in value to a Queen? How could they be, given that having 9 pawns on the board is ILLEGAL?!?

  14. PART II:

    In an attempt to gain additional understanding, I gave my trusty "second" GM Stockfish the task of analyzing the position overnight. Note that the first 5 moves (as given by Chess Tempo) do NOT correspond to the first 5 moves proposed by GM Stockfish. Here are the results after 22 hours plus, with the alternative count set at 15.

    D57 +8.62 1.Nd6 Re1 2.Rxe1 Rf8 3.h4 Ne6 4.Qe3 Ng7 5.Qe5 h6 6.Kh2 Qxe5 7.Rxe5 Rg8 8.Rf3 Kh7 9.Re7 Kg6 10.Rg3+ Kf6 11.Rf7+ Ke5 12.Nxb7 Kd4 13.Na5 Re8 14.Rfxg7 c5 15.c3+ Ke5 16.bxc5 Rc8 17.c6 Kd6 18.c7 Kc5 19.R3g6 Kb5 20.Nb7 Ka4 21.Nd6 Rxc7 22.Rxc7 Kxa3 23.Rg3 Ka4 24.Rb7 h5 25.Rb4+ Ka3 26.Nf5 Ka2

    D56 +5.62 1.Rxg5 Qxg5 2.Qc3+ Kg8 3.h4 Re3 4.Qa1 Qg6 5.Nxe3 Re8 6.Rf3 Qg7 7.Qf1 Qe7 8.Qf2 d4 9.Nf1 Rd8 10.Rf4 h5 11.Kh2 a5 12.Ng3 Rf8 13.Qxd4 Rxf4 14.Qxf4 axb4 15.axb4 Qe6 16.c3 Kg7 17.c4 b5 18.c5 Qg6 19.Qe5+ Kf8 20.Nf5 Qe6 21.Qg7+ Ke8 22.Nd6+ Kd8 23.Qh8+ Kd7 24.Qc8+ Ke7 25.Qxe6+ Kxe6 26.g4 hxg4 27.Kg3 Kf6 28.Kxg4 Kg6 29.h5+ Kg7

    D56 +4.89 1.Ne3 Qe5 2.Ng4 Qg7 3.Nf6 Re1 4.Rxe1 Qxf6 5.Kg1 Rg8 6.Rf1 Qe5 7.Qe3 Qxe3+ 8.Rxe3 Ne4 9.Rf7 Rg7 10.Rf8+ Rg8 11.Rxg8+ Kxg8 12.a4 Kf7 13.a5 h6 14.Kf1 Nd6 15.Rf3+ Kg6 16.Rf8 c5 17.bxc5 Nc4 18.Ke2 Nxa5 19.Rd8 Nc6 20.Rxd5 a5 21.Rd6+ Kg5 22.Rd7 Kf6 23.Rxb7 Ke6 24.Kd2 Kd5 25.h4 Kxc5 26.Kc1 a4 27.g4 Ne5 28.g5 h5 29.Rh7 Kd5 30.Rxh5 a3 31.Kb1 Nf3 32.Rh7 Ke5 33.g6

    D56 +1.95 1.Kg1 Rf8 2.Qe3 Ne4 3.Rg7 Nd6 4.Rxh7+ Kxh7 5.Qh3+ Kg8 6.Qg4+ Kh8 7.Qh5+ Kg8 8.Nh6+ Kg7 9.Rxf6 Rxf6 10.Ng4 Re6 11.Qg5+ Kh8 12.h3 Rg8 13.Qh4+ Kg7 14.Ne5 Rge8 15.Qg5+ Kf8 16.Nd3 Ne4 17.Qf5+ Rf6 18.Qh7 Re7 19.Qh8+ Kf7 20.Kh2 Nd6 21.a4 Nf5 22.Qh5+ Kg8 23.Qg5+ Kf7 24.a5 Nd6 25.Ne5+ Ke6 26.Ng6 Re8 27.Qh6 Rf7 28.h4 Kd7
    D56 +0.51 1.Rg4 Rf8 2.Kg1 Rae8 3.h3 b5 4.Rg3 Re4 5.Qd2 Ne6 6.Rgf3 Ng5 7.Rf4 Rxf4 8.Qxf4 Ne4 9.g4 h5 10.Kg2 Kh7 11.Qe3 Rg8 12.Nd4 Qg6 13.Rf4 hxg4 14.hxg4 Qh6 15.Nf5 Qg5 16.Qa7+ Kh8 17.Qd4+ Kh7 18.Kf3 Rf8 19.Qe5 Qf6 20.Qxf6 Rxf6 21.Ke3 Rg6 22.Nh4 Rh6 23.Nf3 Kg8 24.Kd4 Re6 25.Ne5 Nd2 26.Rf2 Nc4 27.Nxc4 Re4+ 28.Kc5

    D56 +0.39 1.Qd1 Ne4 2.Rgf3 Rf8 3.c4 Qe5 4.cxd5 cxd5 5.Nh6 Rxf3 6.gxf3 Rf8 7.Ng4 Qf5 8.Qd4+ Nf6 9.a4 h6 10.Qc3 Qf4 11.Ne5 Rg8 12.Rg1 Rxg1+ 13.Kxg1 Qf5 14.a5 Kg8 15.Kf1 Ne8 16.Qd4 Nf6 17.h4 Qh3+ 18.Ke2 Qh2+ 19.Kd3 Qh1 20.Kc2 Qh2+ 21.Kb3 Qe2 22.f4 Qe4 23.Qxe4 Nxe4 24.Kc2 Nd6 25.Kd3 Nf5 26.h5 Kg7

  15. PART III:

    D56 +0.26 1.Nd4 Qe5 2.Nf5 Ne4 3.Rg7 Re6 4.Rf7 Rae8 5.g4 Rg6 6.Rxb7 Rf8 7.Qe3 d4 8.Qd3 Nd6 9.Re7 Qd5+ 10.Rf3 Nxf5 11.gxf5 Rg5 12.Qe4 Rfxf5 13.Qxd5 Rxd5 14.Rc7 c5 15.Rf8+ Rg8 16.Rff7 Re8 17.Rxh7+ Kg8 18.Rhg7+ Kh8 19.bxc5 Rxc5 20.Rh7+ Kg8 21.Rxc5 Kxh7 22.a4 Re3 23.a5 Kg7 24.Kg1 Kf7 25.Kg2 Ke6 26.h4 Kd6 27.Rc4 Re5 28.Kf2 Kd5 29.Rc8 Rh5

    D56 +0.22 1.c3 Re4 2.Kg1 Rf8 3.h4 Ne6 4.Rgf3 Qe5 5.g3 a5 6.R1f2 axb4 7.axb4 Re1+ 8.Kg2 Qe4 9.Qxe4 dxe4 10.Re3 Rxe3 11.Nxe3 Rxf2+ 12.Kxf2 Nc7 13.Nc2 Nb5 14.c4 Nd6 15.Ne3 Nf7 16.c5 Ne5 17.Ke2 Kg7 18.Nf5+ Kg6 19.Nd6 Nd3 20.Ke3 Nxb4 21.Kxe4 h5 22.Nxb7 Kf6 23.Nd8 Na6 24.Nxc6 Nxc5+ 25.Ke3 Ne6 26.Kf3 Ng7 27.Nd8 Ke5 28.Nf7+ Kf6 29.Nd6

    D56 +0.19 1.Nh4 Qe5 2.Nf5 Ne4 3.Rg7 Re6 4.Rf7 Rae8 5.Rxb7 Rf8 6.g4 Rg6 7.Qe3 d4 8.Qh3 Nf6 9.Ng3 h6 10.Rf5 Qe1+ 11.Qf1 Re8 12.g5 hxg5 13.Ra7 Ng4 14.Rf8+ Rg8 15.Rff7 Qxf1+ 16.Nxf1 Rg6 17.Kg2 Nh6 18.Rh7+ Kg8 19.Ng3 Ng4 20.Nf5 Ne3+ 21.Nxe3 dxe3 22.Rhe7 Rxe7 23.Rxe7 Rd6 24.Kf3 Rd2 25.c3 Rc2 26.Rxe3 Rxh2 27.Kg4 Rg2+ 28.Kf5 Kf7 29.a4 g4

    D56 +0.16 1.Re3 Rxe3 2.Nxe3 Qe5 3.Ng4 Qg7 4.Qf5 Ne4 5.g3 Re8 6.Rf4 Nd6 7.Qd3 Re4 8.Qf3 Rxf4 9.Qxf4 Qe7 10.Ne5 Kg7 11.Kg2 Qf6 12.Qg4+ Kh6 13.Qe2 Qf5 14.a4 Kg7 15.h4 Qe6 16.Qh5 h6 17.Qg4+ Qxg4 18.Nxg4 Nc4 19.Kf3 Na3 20.Ne3 Kg6 21.g4 d4 22.Ng2 Nxc2 23.Nf4+ Kf6 24.Nd3 b6 25.Ke4 a5 26.bxa5 bxa5

    D56 +0.16 1.h3 Ne4 2.Rgf3 a5 3.bxa5 Rxa5 4.Rf4 Ra4 5.Qe3 Rc4 6.Kg1 Qc3 7.Qd3 Rf8 8.Nh6 Rxf4 9.Rxf4 Ng5 10.Rxc4 Qxd3 11.cxd3 dxc4 12.dxc4 Ne4 13.Nf7+ Kg7 14.Nd8 Nc5 15.a4 Nxa4 16.Nxb7 Kf6 17.Kf2 c5 18.Kf3 Nb2 19.Nxc5 Nxc4 20.Kf4 Nb6 21.Kg4 Nd5 22.g3 Kg6 23.Ne6 Nf6+ 24.Kf3 Kf5 25.Nf4 Kg5 26.h4+ Kf5 27.Ne2 h5 28.Nf4

    D56 +0.14 1.h4 Ne4 2.Rgf3 Rg8 3.Kg1 Rae8 4.Rf4 Rg6 5.Ne3 Qe5 6.Rf5 Qb2 7.g4 Nd6 8.R5f4 Rge6 9.Ng2 Qg7 10.g5 Re4 11.Rf6 R4e6 12.Rxe6 Rxe6 13.Qf3 h6 14.Qg4 Re4 15.Qg3 Re6 16.Nf4 Re8 17.Nh5 Qd4+ 18.Kg2 hxg5 19.hxg5 Re2+ 20.Kh3 Re3 21.Rf3 Rxf3 22.Qxf3 Kg8 23.Nf6+ Kg7 24.Nd7 Ne4 25.Qf8+ Kg6

    D56 +0.13 1.a4 Re4 2.Qd2 h6 3.Kg1 Rf8 4.Re3 Rxe3 5.Nxe3 Qe7 6.Rxf8+ Qxf8 7.Ng4 Kh7 8.Nf2 Qf5 9.Nd3 Qg4 10.Kh1 Ne4 11.Qe1 h5 12.a5 h4 13.Qf1 Kg7 14.Qf3 Qg5 15.Kg1 Nd6 16.Qf4 Qxf4 17.Nxf4 Kf6 18.Kf2 Kf5 19.Nd3 Ke4 20.g3 hxg3+ 21.Kxg3 Ke3 22.Ne5 Ke4 23.Nf3 Nf5+ 24.Kf2 Ng7 25.Ke2 Ne6 26.Ne1 c5 27.bxc5 Nxc5 28.h4 Kf5 29.Nd3

    D56 0.00 1.c4 Ne4 2.Rg4 dxc4 3.Qc2 Re5 4.Ne3 Nf2+ 5.Rxf2 Rxe3 6.g3 Rf3 7.Rf4 Rxf4 8.Rxf4 Qe6 9.Qc3+ Kg8 10.Qxc4 Qxc4 11.Rxc4 a5 12.Kg2 axb4 13.axb4 Kg7 14.Kf3 Ra4 15.h4 h5 16.Rd4 b6 17.Rd7+ Kg8 18.Rd4

    D56 0.00 1.Ne7 Qxe7 2.Qd4+ Qg7 3.Qxg7+ Kxg7 4.Rxg5+ Kh8 5.Kg1 Re7 6.Rf4 Re1+ 7.Kf2 Rc1 8.Rf7 Rg8 9.Rxg8+ Kxg8 10.Rxb7 Rxc2+ 11.Kf1 Rc1+ 12.Ke2 Rc2+

  16. Thanks Robert. The conculsions I came up with the other day was the book move was best, RxN worked, Ne4 was unclear and pushing the knight with h4 was risky for white.

  17. PART IV:

    Another 12 hours spent “investigating” just the responses to the “best” move 1. Nd6. A grande finale in the theater of the absurd: I for one find it ridiculous to imagine that I will ever SEE a checkmate taking 34 moves, no matter how forcing the individual moves might be! GM Aagaard’s observation is apropos: And the rest is just a lack of technique…

    This reminds me of the engineer (with a measured IQ of 185 and two Masters degrees) who worried about a "hole" in his equations of motion for a 688-class submarine simulator - when it reached the speed of sound UNDERWATER, his equations failed. I did my best to assure him that the "hole" in his equations would NOT be a problem.

    I’m done.

    D55 -9.86 1...Re1 2.Rxe1 Rf8 3.h4 Ne6 4.Qe3 Ng7 5.Qe7 b6 6.Kh2 d4 7.Qxf6 Rxf6 8.Re7 Rg6 9.Nf7+ Kg8 10.Nh6+ Kf8 11.Rf7+ Ke8 12.Rxg6 hxg6 13.Rxg7 c5 14.Rxg6 c4 15.Kh3 d3 16.cxd3 c3 17.Rc6 Ke7 18.Rxc3 Ke6 19.Rc4 a5 20.Ng4 b5 21.Rc1 Kd7 22.bxa5 Kd6 23.a6 Ke6 24.a7 Kd6 25.a8=Q Ke7 26.Qa7+ Kd8

    D55 Mate -34 1...Qxd6 2.Qd4+ Kg8 3.Rxg5+ Qg6 4.Qf6 Rf8 5.Rxg6+ hxg6 6.Qxg6+ Kh8 7.Rxf8+ Rxf8 8.h4 d4 9.Kh2 b6 10.Qxc6 Kg7 11.Qd7+ Kh6 12.Qxd4 Rg8 13.Qxb6+ Rg6 14.Qa7 Rg4 15.Qe7 Rg6 16.Qf7 Rg7 17.Qf6+ Kh7 18.Qxa6 Rf7 19.Qc4 Kg6 20.b5 Rf5 21.b6 Rf7 22.Qxf7+ Kxf7 23.b7 Ke6 24.h5 Kd6 25.b8=Q+ Kc5 26.Qb7 Kd4 27.h6 Ke5 28.h7 Kd4 29.Qb4+ Ke3 30.Qc3+ Ke4 31.Qc4+ Ke3

    D55 Mate -22 1...Nf3 2.Nxe8 Rxe8 3.Rgxf3 Qe5 4.Rf7 Qe4 5.Qg3 Qg6 6.Qc7 h6 7.Rf8+ Rxf8 8.Rxf8+ Qg8 9.Qf7 Qxf8 10.Qxf8+ Kh7 11.h4 d4 12.Qf7+ Kh8 13.Kh2 d3 14.cxd3 h5 15.Qxh5+ Kg8 16.Qg5+ Kf7 17.h5 a5 18.h6 a4 19.Qf5+ Ke7 20.h7 Kd6 21.h8=Q Kc7 22.Qfe5+ Kd7 23.Qhe8#

    D55 Mate -15 1...Re3 2.Rxf6 Rxd3 3.cxd3 Kg7 4.Re6 h6 5.h4 Rf8 6.hxg5 h5 7.g6 c5 8.Ne8+ Rxe8 9.Rxe8 cxb4 10.Re7+ Kf6 11.g7 Kxe7 12.Rg6 Kd7 13.g8=Q Kc7 14.Qxd5 bxa3 15.Qd6+ Kc8 16.Rg8#

    D55 Mate -13 1...Qxf1+ 2.Qxf1 Re6 3.Qa1+ d4 4.Qxd4+ Kg8 5.Rxg5+ Rg6 6.Qe5 Rf8 7.Nf5 Rxf5 8.Rxf5 h6 9.Qe7 Rg7 10.Rf8+ Kh7 11.Qe4+ Rg6 12.Rf7+ Kh8 13.Qe5+ Kg8 14.Qe8#

    D55 Mate -11 1...Qg6 2.Rxg5 Rf8 3.Rxg6 Rxf1+ 4.Qxf1 hxg6 5.Qf6+ Kh7 6.h4 Rg8 7.Nf7 Re8 8.Kh2 d4 9.h5 gxh5 10.Ng5+ Kg8 11.Qg6+ Kf8 12.Qf7#

    D55 Mate -11 1...Qe5 2.Rxg5 Qxd6 3.Qd4+ Re5 4.Rxe5 Kg8 5.Rg5+ Qg6 6.Rxg6+ hxg6 7.Qf6 Re8 8.Qxg6+ Kh8 9.Qxe8+ Kg7 10.Qf7+ Kh6 11.Rf5 b5 12.Rh5#

    D55 Mate -11 1...Qg7 2.Rxg5 Qxg5 3.Nf7+ Kg8 4.Nxg5 Re7 5.Qf5 h6 6.Qg6+ Rg7 7.Qe6+ Kh8 8.Rf6 hxg5 9.Rh6+ Rh7 10.Qf6+ Kg8 11.Rg6+ Rg7 12.Qxg7#

    D55 Mate -9 1...Qe7 2.Qd4+ Kg8 3.Nf5 Kf7 4.Nxe7+ Ke6 5.Nxd5 Kd7 6.Qg7+ Nf7 7.Rxf7+ Kd6 8.Rd7+ Ke6 9.Re3+ Kf5 10.g4#

    D55 Mate -9 1...Rf8 2.Rxf6 Rxf6 3.Qd4 Rf8 4.Rxg5 c5 5.Qe5 h6 6.Rg6 Kh7 7.Rxf6 Rxf6 8.Qxf6 cxb4 9.Ne8 bxa3 10.Qg7#

    D55 Mate -9 1...Re6 2.Rxf6 Rxf6 3.Qd4 Rf8 4.Rxg5 c5 5.Qe5 h6 6.Rg6 Kh7 7.Rxf6 Rxf6 8.Qxf6 cxb4 9.Ne8 bxa3 10.Qg7#

    D55 Mate -9 1...h6 2.Rxf6 Re1+ 3.Rf1 Rxf1+ 4.Qxf1 Rg8 5.Nf7+ Kh7 6.Qf5+ Kg7 7.Nxg5 hxg5 8.Rxg5+ Kh6 9.Rxg8 a5 10.Qg6#

    D55 Mate -9 1...Rad8 2.Rxf6 Rxd6 3.Qd4 Re1+ 4.Rf1+ Kg8 5.Rxg5+ Rg6 6.Rxg6+ hxg6 7.Rxe1 Kf7 8.Qf4+ Kg8 9.Re7 d4 10.Qb8#

    D55 Mate -8 1...Qf4 2.Rxf4 h6 3.Rf1 Re4 4.Nxe4 dxe4 5.Qd6 Kg7 6.Qe7+ Kg8 7.Rf6 Kh8 8.Rxh6+ Kg8 9.Rxg5#

    D55 Mate -8 1...Qb2 2.Nxe8 Rxe8 3.Rxg5 h6 4.Rg6 Re4 5.Qg3 Qf6 6.Rgxf6 Rg4 7.Qxg4 Kh7 8.Qg6+ Kh8 9.Rf8#

  18. So,
    1. Looking for the visible salient cues
    2. Thinking for the hidden salient cues
    3. Stitching the salient cues together in a narrative

    1 can be automated
    3 cannot be automated
    I suspect that 2 can be automated too. Take for instance this position. Overlooking the Knight LoA and the Queen LoA seems to be a matter of learning the habit to look for them. Or maybe 2 is just part of 1.

  19. Think of all the varied mates with Knight(s). Philidor Legacy and numerous smothered mates, Short Anastasia on the 7th rank, long Anastasia on the 6th rank, Knights on f7 killing the King in the cornetvarious Arabian Mates and Odd 2 Knights Mates and Varied Bishop and Knights combo mates... Add on top of this we often have 2 squares that look like good knights locations, its no wonder we miss forks in these sequences.

  20. OTOH, if I write a post which is essentially about line of attack and I forget to look at 50% of them, I take it that I have an issue that needs to be worked on.

  21. Some tactics end with gain of wood, some with promotion, some with a winning endgame and some with an invasion. The reason for this post is that with an invasion Stockfish often says, "you are winning", while I don't quite see the continuation. And often even lack the feel that it is winning. It is not necessary to see a mate in 35, but at least the gut feeling "this is winning" would already be nice.

  22. So this is the hypothesis. Thinking and fiddling around is the way to make the hidden salient cues visible. Once made visible, they must be absorbed. All this happens in the study room.

  23. In Aagaard's Attacking Manual 2 (AM) he annotates many games where he points to current strong players who miss mates and gain of wood on both sides of the board. He concluded that even these strong players aren't sufficiently well versed in tactics and mate recognition. What bothers me when viewing master games in, I haven't a clue why a player resigns .....

  24. PoPLoAFun is a useful mnemonic for reminding us to "LOOK" at the important aspects in a given position: the points of pressure (regardless of how we distinguish them), the lines of attack (regardless of whether the pieces involved move rectilinerally or not), and the functions of the pieces (which constrain the activity of the pieces). The purpose behind emphasizing extending the auras of pieces to the edge of the board is (again) a reminder to "SEE" through obstacles along a line of attack (which the formal rules of chess constrain—a piece CANNOT move through its own pieces, and can only go as far as the first opponent’s piece encountered along a line), not to apply that advice literally in all circumstances. In short, “it depends” is an accurate assessment of all such advice.

    My initial observations on the lines of attack was intentionally limited to lines. [As my wife is fond of pointing out, I am definitely “left-brained,” to the nth degree.] I was aware of the potential Knight forks and the subsequent operations but was trying not to address anything other than lines of attack, such as variations or even the knight moves. This is not an ex post facto excuse for me not grasping the intent behind the question: “Can you describe the LoA landscape?”. I have been hesitant to confess this, since it may seem as if I am trying to justify my “blindness” by claiming I saw everything initially.

    All of the various thinking techniques are part of the collection of “mini-skills” needed to create overall chess skill. Again, the metaphor of the bricks (mini-skills) and the wall (overall skill) is useful as an analogy.

    As for reaching an overall evaluation, I still consider Botvinnik’s simile of “escape from the swamp” to be apropos.

    Thinking will always be required to deal with the uniqueness of any position. No matter how much we absorb as patterns, we still have to fit it all together in a concrete solution.

  25. This is the point I'm trying to make. Where do the visible salient cues originate? They start out as hidden salient cues that you do not see. A thinking process makes them visible. When you repeat a set of problems 30 times, most intricacies become visible. They are no longer hidden, and there is no longer a need to think about them. In fact they transferred from system 2 to system 1, from knowledge to skill and from hidden to visual.

    All this happens ideally in the study room. In the study room you can use side wheels like mnemonics, repetition, Stockfish and all sorts of help like consulting your fellow commenters. Behind the board these auxiliary tools are not allowed nor practical. You have no time for that.

    Behind the board you just see what is going on. The only thing you use system 2 for is stitching together what you see. Ideally.