The Bad Pin

A pin is a restrictive contact that either prevents a piece from moving because doing so would violate the rules of the game (absolute pin), or that discourages moving the piece because the consequences could be dire (relative pin). Pins can be potent weapons in the chess struggle (see "A Lesson in Pins").

Relative pins are double edged. They can backfire, presenting the player facing the pin with an opportunity. Many of my students the past two weeks have seen this position from a game I played 16 January on Lichess.

White to move

After 5...Bg4??

How should White deal with the pin on the knight? Once you understand certain patterns, the correct answer is instantaneous. 

Evidently I am not the only player who has had this exact position. The position just before I played 8.Qxf7# has been examined in the ChessBase cloud more than 1500 times. Certainly some of the games that could have led to the moves in my game continued 6.Ne5 Bxd1 7.Bxf7#. It seems likely that a few players of the Black pieces also would have found 6...Be6 (the best choice after White exploits the bad pin).

Years ago, perhaps 1999, I bought and began reading Georges Renaud and Victor Kahn, The Art of the Checkmate, trans. W. J. Taylor (1953). I wrote about this book and how it first came to my attention in "Checkmate Patterns) (2015) and again in "Learning Checkmate (Or Teaching It)" (2021). I am rereading it, now in a new translation that has algebraic notation.

The Art of the Checkmate is my first recommendation when players are looking to learn checkmate patterns. Renaud and Kahn do far more than present basic patterns and then offer exercises. They offer detailed discussion of the variability of the basic pattern and how to bring it about. They use mostly full games. The chapter, "Legal's Pseudo-Sacrifice" (11-21) offers 17 complete games arranged by what they refer to as the "four aspects" of Legal's mate. They explain:

First and foremost we ask you not to learn it by heart but to grasp the precise mechanism, to understand that the bishop on g4 in "hanging", that is to say exposed to capture if the knight moves to threaten mate. But this mechanism appears in many positions as a latent threat and the opponent, if he pins your king's knight, is obliged to take this into account.
The Art of the Checkmate, trans. Jimmy Adams (2015)

I missed my chance to show the knowledge I should have acquired from the book in this blitz game played in 1999 on the Internet Chess Club.

White to move

Cleary, 9.Nxe5 is the correct move. I played 9.Nbd2, still managed to get a clear advantage, worked it into a decisive advantage, and lost on time in the endgame.

In 2000, I showed further incomprehension by maneuvering my way into the losing side of one of the combinational motifs enabled by "the bad pin".

White to move

My opponent understood the ideas and seized a clear advantage.

7.Bxf7+ Kxf7 8.Ng5+ Ke8 9.Qxg4

White has a decisive advantage and went on to win.

Genesis of the Instruction

It might be a stretch to claim that Renaud and Kahn invented the genre of checkmate pattern books. The manuscripts of Gioachino Greco, and many books grounded in these manuscripts offer more in the way of elementary checkmates than any sort of positional insight. But, when it comes to naming and classifying checkmate patterns, I know of nothing earlier than The Art of the Checkmate.

In the annotations to Kermer de Légall's famous game in the Jimmy Adams translation, Renaud and Kahn credit Emanuel Lasker with articulating a general principle of open games: "it is not always advisable to pin the opponent's king's knight before he has castled" (the 1953 translation makes no reference to Lasker). They are referring to lectures Lasker presented in London in 1895 and which were later published in outline as Common Sense in Chess (1917). I presented "Lasker's Rules" to my students and on Chess Skills in 2013, and then discussed Erik Kislik's (Applying Logic in Chess [2018]) critique in "Knights Before Bishops" (2018). It is notable that Renaud and Kahn qualify Lasker's rules in a manner that anticipates Kislik's critique. 

Lasker, Common Sense in Chess presents two short games at the beginning of the chapter. It is not clear that they derived from actual play as all the instances of his two miniatures that I find in the database are relatively recent (late-twentieth century to the present). This position arose in the second.

Black to move

6...Nxe4 7.Bxd8 Bxf2+ 8.Ke2 Bg4#

Renaud and Kahn begin with Legall's well-known game. However, the version they offer differs from that found in George Walker, A Selection of Games at Chess (1835). Edward Winter inquired in 2008 about the earliest known publication of Legall's game (Chess Notes 5720, 18 August 2008). Dominique Thimognier has been researching Legall and published some of the results in French at Heritage des Echecs Francais.

The variation presented in Walker is unsound. White blunders with 5.Nxe5. Yet, the Walker variation is the one found in ChessBase Mega 2020. Chessgames.com has the variation presented in Renaud and Kahn, but with White's rook on a1 absent.

Although there is plenty to doubt about the original game, the endless variations of the ideas have appeared in a great many games. Renaud and Kahn explicate the possibilities well.

Practice

I created an interactive lesson on Lichess.org with some instructive games and 20 exercises. The Study is called "The Bad Pin". I may add to it as I find time. Take a look. Let me know what you think.

A Lesson in Pins

In my after school chess club at Saint George's School yesterday, I presented the game below to the students to highlight some basic principles for using pins effectively.

The player with the White pieces was William Lewis (1787-1870), a prolific chess author best remembered as one of those who hid inside the infamous fake chess playing machine called "The Turk".* Lewis was a student of Jacob Henry Sarratt, England's best player. I am drawn to Lewis because his Gioachino Greco on the Game of Chess (1819) offers more of Greco's model games than can be found in databases (see "Gioachino Greco on the Game of Chess"). Some of the positions in his other instructional books also are a regular part of my teaching.

Lewis,William -- Keen,Eric [C56]
London Casual Games London, 1817

1.e4 e5 2.Nf3 Nc6 3.Bc4 Bc5 4.c3 d6

4...Nf6 is the most popular move today, but 4...d6 is solid.

5.0-0 Nf6 6.d4

6.d3 seems better.

6...exd4 7.cxd4 Bb6 8.h3

Black to move

8...Nxe4

8...0-0 has led to better results for Black in current master play.

9.Re1

The first pin. We use the term pin when two pieces are attacked along a file, diagonal, or rank such that the one in front cannot move (absolute pin) or by moving exposes a piece of greater value to capture (relative pin).

9...d5?

A mistake.

9...0-0 is best 10.Rxe4 d5 restores the material balance 11.Bxd5 Qxd5 and White has a slight advantage.

10.Bxd5

10.Bg5 is also strong

10...Qxd5 11.Nc3

Piling on the pinned knight wins back the material and maintains substantial pressure on Black's position.

11...Qd8

White to move

12.Rxe4+!+-

12.Nxe4 0-0 leaves White with only a slight advantage (12...Nxd4?? 13.Bg5! [13.Nf6+ Kf8 14.Re8+ Qxe8 15.Nxe8 Kxe8 16.Nxd4] 13...Nxf3+ 14.Qxf3 Qd4 15.Nd6+).

12...Ne7

Moving another piece into a pin makes Black's troubles worse.

12...Kf8 and Black cannot castle. This move is Black's best choice. In either case, White already has a technical win.

13.Qe2

Here, castling would lose the knight.

13...Be6 14.Bg5

Pinning the knight again

14...Qd6 15.Bxe7

Black to move

15...Kxe7

Now the bishop is pinned.

15...Qxe7 16.d5 0-0-0 17.dxe6+-

16.d5 Rhd8 17.Ng5

Piling on. The manner with which Lewis increases the pressure on Black's pinned pieces is instructive. 17.dxe6 is just as good.

17...c6 18.Nxe6

Threatens discovered check

18...fxe6

18...Rd7 19.Nc7+ Kd8 20.Nxa8

19.Rxe6+

Fork

Black to move

19...Qxe6

19...Kf8 20.Rxd6 Rxd6 21.Re1

20.Qxe6+ Kf8 21.d6 Re8 22.Qf5+

22.Qc4 is stronger. Whites material superiority and less vulnerable king makes the advantage overwhelming in any case.

22...Kg8 23.Ne4

White has a checkmate idea that Black does not find a way to stop.

Black to move

23...Rf8

23...h6 offers more stubborn, albeit helpless defense.

24.Qe6+ Kh8

White to move

25.Ng5

25.d7 is simple, but Lewis wants to execute a picturesque checkmate.

25...Bxf2+

Black strikes back to win a pawn and check the king, but there is no follow up as Black's lacks sufficient force for a counterattack.

26.Kh2 Rae8 

Moves into the checkmate that Lewis hoped for in bringing up his knight.

White to move

27.Nf7+ Kg8

27...Rxf7 28.Qxe8+ Rf8 29.Qxf8#

 28.Nh6+ Kh8 29.Qg8+ Rxg8 30.Nf7# 1-0

*See Tom Standage, The Turk: The Life and Times of the Famous Eighteenth-Century Chess-Playing Machine (2002).

Level 5

It is not easy to judge the difficulty level of a chess exercise. In a correspondence game fifteen years ago, I spent a full two hours or more finding the only non-losing move where there were multiple checkmate threats. Last October, I showed it to a friend at the Spokane Chess Club and he solved it in a few seconds.

Black to move

In Tactical Training (2021), Cyrus Lakdawala rates exercises on a scale of 1 to 5. He offers the suggestion that a mate in one illustrating the Dove Tail Mate should be classified as 0.5 because it is so easy (23). Nonetheless, several of my online students struggled with similar exercises in December (23). He states, "Level 3 is a problem that an 1800-rated player should solve without breaking too much of a sweat" (8), but I struggled with a couple of those this morning. "Levels 4.5 to 5 means that even a 2400-rated player may sweat to solve it" (9), but I solved one without much difficulty while eating breakfast this morning.

The Level 5 exercise that I solved this morning is the conclusion of a study by Vassily Smyslov published in New in Chess Magazine in 2000. I found the full study in Harold van der Heijden's Endgame Study Database.

It is number 132 in Tactical Training (114). Maybe you will do as well as I did.

White to move

I reviewed Tactical Training for Amazon last July.

More Notes on Berger

Johann Berger, Theorie und Praxis der Endspiele (1890) systematically examines practical chess endings in a manner that ushered in the modern theory of the endgame. The book's availability has been enhanced by Google Books.

During my reading yesterday, some underpromotion exercises captured my interest. Berger credits Carl Ferdinand von Jaenisch as the composer. I played them out against Stockfish on my iPad and found the second one required some calculation to get the knight to its proper posting.

White to move

1.Rxg5+ Rxg5 2.fxg5 h2 3.g6 Kh3 4.g7 h4

White to move

White must underpromote to a bishop or knight to avoid stalemate. In this instance, a bishop is the better choice, but a knight can win.

Berger's second exercise from Jaenisch differs in the placement of two pawns.

White to move

1.Rxg5+ Rxg5 2.fxg5 h2 3.g6 Kh3 4.g7 h4

Now, while a bishop does not stalemate, it also cannot win. White must play 5.g8N.

5...Kg4

White to move

Berger's solution continues with 6.Nf6+. I played 6.Ne7, and the tablebases favor 6.Kxh2.

Preceding these studies, Berger offers a brief explanation of the square of the pawn. Following these, is a section on the opposition with several illustrative positions, culminating in this important one from Giambattista Lolli, published in 1763.

White/Black to move

White to move wins; Black to move draws. For some reason, I found the draw hard to believe, but I've practiced the position against students many times since learning it more than ten years ago. Winning with White to move is one one of my requirements for the Bishop Award in my Scholastic Chess Awards.

Notes on Berger

David Hooper states that Johann Berger, Theorie und Praxis der Endspiele (1890) is "the first comprehensive book in modern times devoted wholly to the practical endgame" (Golombek's Encyclopedia of Chess [1977], 101). In 2009, Google digitized a copy from Harvard Library, making it readily accessible to those interested in the history of the theory of the endgame. Although Hooper states Berger's text, "would not today be regarded as adequate for practical use", I am finding much that is instructive and interesting as I have been reading through it this morning.

Berger makes a point in the first pages to distinguish endgame theory from studies. The endgame, he asserts, "comprises only the battle of a few chess pieces against correspondingly low defensive forces" (2). Compositions leading to checkmate, stalemate, or a draw must be distinguished from endgame theory because, "the chess pieces have a completely different meaning and are used differently than in actual endgames" (2). He presents some illustrations of studies that are not endgames, beginning with a composition by Bernhard Horwitz.

White to move

Horwitz 1884 

White checkmates in six moves. Berger points out that the play of the pieces resembles the middlegame, and also that White's rook is superfluous. In the endgame, "the best possible use of the power of each individual piece should be expressed" (3), Berger opines. He offers:

White to move

1.Kc4 c1Q

Or 1...Ka1 2.Qd2 (to avoid an underpromotion threat)

2.Kb3 and checkmate in a few moves.

Berger's eighth example highlights two ways that a theoretical draw of rook vs. bishop is reached from the following position.

White to move

1.f7 Bd5 2.f8Q Rg8

Or 

1.Rc1+ Kh2 2.f7 Bd5 3.f8Q Rg8

Following this clarification of endgame theory as distinct from studies, Berger shows elementary checkmates--queen, rook, two rooks, two bishops, and then no less than five positions from which checkmate by bishop and knight can be executed.

Then he turns to the knight. Two knights, as we know, can only stalemate. What about three knights? Berger presents a composition of his that was published in Osterreichische Lesehalle (1889).

White to move

When I played this position against the computer, it opted for a line given by Berger as a variation. I was able to coordinate my pieces and win easily.

1.Rxe7 Qd4+

1...Qxe7 leads to 2.c8N+ winning the queen and leading to checkmate. Berger finds a mate 15 moves from the diagram.

Seeking Understanding

Five years ago, I posted "Two Endgame Compositions", giving only the solution to the second. This week I was asked to provide the solution to the first, an 1888 composition by Johann Berger that was first published in Columbia Chess Chronicle. The past two mornings, I have been studying the solution with an aim to understand every move. Although the maneuvers appear complex, they are based on some simple ideas.

White to move

J. Berger, 1888

1.Qb8

The only winning move, according to the tablebases. It forces the light-squared bishop to move because of the checkmate threat Qh2#.

1...Bc4

Threatens Be6+, followed by Bf2+ (or Bh2+).

Other moves lose more quickly.

1...Be2 2.Qf4 (see at move 4 below)
1...Bd3 2.Qf4
1...Bb5 2.Qxb5 Ba7 3.Qd5
1...Ba6 2.Qg8 Bb7 3.Qh7 Bc8+ (3...Bf2 4.Qxb7) 4.Kg3+

2.Qe5

Prevents the check while keeping the dark-squared bishop immobile.

2.Qd6 is one move slower. This move is presented as a "cook" in Harold van der Heijden's Endgame Study Database with a line leading to underpromotion of Black's pawn. It is an instructive alternative.

2...Ba6

Threatens Bc8+

2...Bd3 3.Qg5 threatens Qxg2#. 3...Be4 4.Qh4 Bf5+ (4...Bf2 5.Qxe4) 5.Kg3+
2...Be2 3.Qxe2
2...Bb5 3.Qxb5

3.Qc7

Prevents the check while keeping alive the Qh2 threat.

3.Qe1 is one move slower according to tablebases.

3...Bd3

3...Bb5 allows 4.Qg7

(4.Qc1 Is given ! in Genrikh Moiseyevich Kasparian, 888 Miniature Studies [2010]. Pins the dark-squared bishop so a check can be met by Kg3 and then Qh6+ 4...Bf1 5.Qf4 Ba6 6.Qg4; 4.Qb7)

4...Bc6 5.Qh6 Bd7+ (5...Bf2 6.Qxc6; 5...Be3 6.Qxc6) 6.Kg3+
3...Be2 is second best 4.Qg7 Bf3 5.Qa1 Be2 6.Kg3

4.Qf4

Threatening to move to g4 where checks along the c8-h3 diagonal are blocked and Qxg2 is threatened. This move forces the light-squared bishop onto the a8-h1 diagonal.

Black to move

4...Bb5 5.Qg4

Shields the king from check and threatens Qxg2#

5...Bc6

Defends g2

6.Qd1

Pins the dark-squared bishop and prepares Kg3

6...Be4

White to move

7.Kg3

Threatens Qh5+. The complex battle between White's queen and Black's light-squared bishop has concluded. Now, White threatens checks on the h-file, which Black can delay briefly.

7...Bg6

Guards h5

8.Qc1

Threatens Qh6+

8...Bh5

Prevents the check

9.Qa1

Forces the bishop off the h-file.

Black to move

The rest is easy.

9...Be2 10.Qh8+ Bh5 11.Qxh5+ Bh2+ 12.Qxh2#

Knowledge

When does a player refuse a draw offer in a dead drawn position? If time is a factor, such a refusal could make sense. Often a draw offer is refused because a player does not know the position is a draw, or suspects that the opponent does not have the requisite knowledge to hold the position.

I had Black in this position this morning.

White to move

49.b7??

After this error, the game is a dead draw. White should have played 49.g4, or started moving the king towards the b-pawn. I offered a draw after a dozen moves, having reached this position.

White to move

Instead of accepting the draw, my opponent played another 20+ moves, eventually setting a trap with 84.Rh8?? (White's king was on e4). I could take the pawn, stepping into a skewer. Or, I could take the free rook. After I took the rook, White resigned.

I have played similar endgames before in all sorts of time controls (see one example at "Winning" [2016]). I am guided in the knowledge that my king must remain on the seventh rank and the g- or h-file. With the pawn on g6, the king cannot move. I recall reading about this technique in a book that included a discussion of the resulting skewer tactic if the defending king strays.

However, looking through my endgame books, I could not find the remembered passage. Even so several books contain examples that are close enough that an attentive reader can easily derive the relevant knowledge.

The Books

Nikolay Minev, A Practical Guide to Rook Endgames (2004) shows a stalemate trap when the stronger side has a useful f-pawn, but prematurely sets up the skewer (21-22). From Khiut -- Alalin, USSR 1952.

White to move

1.Kf4 Kf7 2.Rh8??

White sets up the skewer.

2...Rxa7 3.Rh7+ Kf6 4.Rxa7 stalemate.

Yuri Averbakh, Chess Endings: Essential Knowledge (1996) shows an interesting drawing idea from Johann Berger (67).

White to move

1.Kf7

Black cannot get to the seventh rank fast enough, but can avoid checks using the Black king as a shield.

1...Kf5 2.Ke7 Ke5 3.Kd7 Kd5 4.Kc7 Kc5 5.Kb7 Rb1+ forcing Black's king back to the c-file.

Although it was fixed in my memory that I learned the technique employed this morning from Averbakh, it is not in Chess Endings: Essential Knowledge. I did find the idea expressed clearly in Edmar Mednis, Practical Rook Endings (1982), but I've known the technique far longer than I've owned this book. Mednis explains, "the stronger side wants to avoid the following two potential problems: immobilizing his Rook and depriving his King of shelter" (22). Both problems exist in the illustrative diagram. My opponent created the first with 49.b7. Pushing the g-pawn forward introduced the second, but there was no way to dislodge my rook from the c-file.

White to move

In his illustrative diagram, Mednis explains both Black's need to keep the king on g7 or h7, and the rook remains on the c-file, leaving only to check White's king when it gets near its pawn.

Two books that I have had for several years and have spent some time reading explain the ideas, too. One of the critically important blue diagrams in Dvoretsky's Endgame Manual (2003) shows the winning idea missed in Minev's example when the stronger side has an f-pawn (152).

White to move

White wins with 1.f6+ because taking the pawn leads to 2.Rf6+ followed by a8Q, while moving in front allows White to set up the skewer with 2.Rh8. Dvoretsky points out that a pawn on the g- or h-file, however, does not present problems for Black. Although Dvoretsky's description of the skewer does not match my recollection, it may be the book from which I learned this idea.

Jeremy Silman, Silman's Complete Endgame Course (2007) offers three pages of analysis with three diagrams with the white pawn on a7, and three more pages and diagrams with the pawn on a6. These are in the endgames for Class A. I recall that I read about that far within days of buying the book when it first came out. His "A key tactical idea" underneath the diagram below comes close to what I recall studying. Black attempted a "queenside trek" (230).

Black to move

So, I may have learned the idea from Dvoretsky, and certainly encountered it in Silman. It may also be in some other endgame books on my shelf. The simple idea appears in many books. My opponent either lacked this knowledge, or suspected that I did. In the end, he set up a skewer threat that was shocking enough I could have fallen for it on impulse. However, I took a few seconds to assess and grabbed the free rook.

Bishop takes Pawn with Check!

Two positions were presented to my elementary students at the after school chess club yesterday. The first occurred in my shortest game in a weekend Swiss. The second position did not occur in Nepomniachtchi,I. -- Carlsen,M., Halkidiki 2003. Cyrus Lakdawala explains in Nepomniachtchi: Move by Move (2021), which was just published, that Carlsen, "even as a newborn infant, wouldn't fall for 8...dxe3??" I explained to the students that Carlsen was not born knowing this tactic, but learned it, just as they can.

My short loss:

Rodriguez,Luis (2211) -- Stripes,James (1472) [B21]

Collyer Memorial Spokane (1), 21.02.1998

1.e4 c5 2.d4 cxd4 3.c3 dxc3 4.Nxc3 d6

Remembering the game incorrectly, I presented my move as 4...Nc6, which is probably a more accurate move order.

5.Bc4 a6?

A waste of time. 5...Nc6 should be played. After 5...Nc6, it is still possible to fail the way I did in the game. For instance, 6.Nf3 Nf6 7.e5 Nxe5?? 8.Nxe5 dxe5. This was the position shown to the students because I was presenting the tactic from a faulty memory.

6.Nf3 Bg4??

Utter foolishness.

7.Ne5+- dxe5

White to move

8.Bxf7+ 1-0

I resigned because I had far better things to do than watching how easily a master would checkmate me from such a horrid position.

Ian Nepomniachtchi (2447) -- Magnus Carlsen (2450) [B06]
Wch U14 Halkidiki GRE, 2003

1.e4 c5 2.c3 d5 3.exd5 Qxd5 4.d4 g6 5.Nf3 Bg7 6.Na3 cxd4 7.Bc4 Qe4+ 8.Be3

The game continued 8...Nh6. 

For the children, however, the error that Magnus Carlsen could see through is worth examining.

After dxe3??

White to move

9.Bxf7+ wins the queen.

9...Kxf7 allows 10.Ng5+ forking king and queen.

9...Kf8 delays the fork one move. 10.Qd8+ Kxf7.

The World Chess Championship between Champion Magnus Carlsen and Challenger Ian Nepomniatchchi begins at 16:30 Friday afternoon in Dubai. That's 3:30 am in my time zone. I may not watch the beginning of the game live, needing some sleep. But, I will check on the progress as soon as I awake.