Showing posts with label Vukovic (Vladimir). Show all posts
Showing posts with label Vukovic (Vladimir). Show all posts

28 October 2022

Problem of the Week

Elementary checkmates

Several years ago, I developed the habit of posting a portion of each week's chess lessons for youth players on Chess Skills. These were labeled with "Problem of the Week". After a few years, I stopped doing these posts weekly, but would post one from time to time. I seem to be slipping back towards the regular habit.

My students this week in the after school club were presented with some checkmate positions.

On Tuesday I presented the first ten moves of a game that I played online the day prior, then asked students to work out the forced checkmate in five. Although the position differs slightly, the five move sequence is identical to one found in Vladimir Vukovic, The Art of Attack in Chess (1965).

Stripes,J. -- Internet Opponent [C10]
Live Chess Chess.com, 17.10.2022

1.e4 e6 2.d4 d5 3.Nc3 dxe4 4.Nxe4 Nf6 5.Bd3 Nxe4

5...Nbd7 has been my choice with Black.

6.Bxe4 Bd6

Both 6...c5 and 6...Nd7 are better.

7.Nf3 0-0 8.Bxh7+?

In this instance, the classic bishop sacrifice leads only to equality with best play.

8...Kxh7 9.Ng5+
Black to move
9...Kg8??

9...Kg6 was necessary 10.h4 Kf6 is best 11.Nh7+ Ke7 12.Nxf8 Kxf8 is best with equality.

10.Qh5+- Re8

Moves into forced checkmate

Black's woes are illustrated by the computer's suggested alternatives:
10...Bb4+ 11.c3; or
10...Qxg5 11.Bxg5

White to move

On Thursday, I first presented a situation that led to a draw in the previous Saturday's youth tournament. After more than a dozen moves, a young player with rook and knight against a lone king admitted inability to force checkmate. I asked a few students to show how they would find checkmate from this position.

White to move
After students showed their methods, I reviewed the process of keeping the Black king in an ever shrinking box. Then I presented a common exercise that Bruce Pandolfini has in his Pandolfini's Endgame Course (1988), 27.

White to move
Any rook move begins the process of delivering checkmate by force in three moves.

White has a mate in three with the rook on any square marked in yellow.

The real challenge was in solving a puzzle that dates from the mid-fifteenth century (before the bishop and queen gained the power they have now). 
White to move
Checkmate must be delivered in 12 moves or less. The rook can only move once was a stipulation of the problem. This problem shows that chess players know how to use opposition and outflanking more than 570 ago.



11 August 2022

Two Pigs

Edward Winter has published several entries in Chess Notes over the years inquiring into the origins of the checkmate pattern often called blind swine. The term "blind swine" for two rooks on the seventh that cannot find checkmate was credited to Dawid Janowsky by Vladimir Vukovic (see CN 5160). Winter seeks a primary source that confirms Janowsky used the term. None have been found. The phrase has been credited to Aron Nimzowitsch as well (CN 3525).

This morning I had two rooks on the seventh and was playing for a draw because I failed to see a resource: my f-pawn could advance to support one of the rooks and produce a different two rook checkmate. In my defense, it was early morning, my first game of the day, and the game was one minute plus one second increment. Such a time control does not produce accurate play.

Stripes,J. -- Internet Opponent [D06]
Live Chess Chess.com, 11.08.2022

White to move

27.b4?! d4 28.exd4 cxd4 29.Rc7+ Kg8??

29...R8e7=

30.Rxa7 Re2+ 31.Kg3 Rd8

31...R2e7 32.Rxe7 Rxe7 33.Rc8+ Kf7 34.Rd8+-

32.Rcc7

White has two rooks on the seventh, but how is this enough to win?

32...d3

White to move

33.Rxg7+ Kf8 34.Raf7+

34.Rxh7 threatens mate.

34...Ke8 35.Rc7 Kf8

White to move

36.Rcf7+

I could have played: 36.Rxh7 Kg8 37.f5! The key move that escaped my notice.37...d2 38.Rcg7+ Kf8 39.f6 and mate comes soon.

36...Ke8 37.Rc7 Kf8 38.Rxh7 Kg8 39.Rcg7+ Kf8 40.Rf7+ Kg8 41.Rfg7+ Kf8 42.Rf7+


White seems to be playing for a draw. I was because my fear of Black's d-pawn rendered the power of my f-pawn invisible.

Black to move

42...Ke8?

42...Kg8 White must find 43.f5, which White has already shown is beyond his capacity.

43.Rc7 Re7

White to move

44.Rh8+

White finds a tactic to create the opportunity that was already on the board. It is not the rooks that are blind.

44.Rcxe7+ Kf8 45.Rb7 Kg8 46.f5

44...Kf7 45.Rh7+ Kf6 46.Rcxe7 d2 47.Rd7 White won on time 1-0

30 March 2022

Classic Bishop Sacrifice: Early History

Gioachino Greco (c.1600-c.1634) is usually credited with the discovery of the classic bishop sacrifice on h7, at least by those who bother to look into the matter historically. A few years ago some writers suggested the sacrifice was of more recent invention. These days, perhaps because Greco's games are better known, most writers have given up on such ideas.

Although the best known early example of the sacrifice comes from Greco, he appears to have learned the idea from Alessandro Salvio (c.1575-c.1640), who published some lines employing the sacrifice in Trattato dell' Inventione et Arte Liberale del Gioco Degli Scacchi (1604).

White to move

In 1996, Edward Winter posed the question in his column, "When was the Bxh7+/Ng5+ attack first played"?* He proceeds to demonstrate Irving Chernev's confusion on the matter, claiming Morphy -- Guibert, Paris, 1858 in Chess Review (April 1950) and in The Chess Companion (1968), while two pages later in this book Chernev suggests Paulsen -- Schwartz 1879. Winter asks, "what about Greco", noting that Chernev includes Greco's game in The 1000 Best Short Games of Chess (1955), where it is game 199 (90). 

The version of the game in Chernev's collection of miniatures is identical to the second variation of the twenty-third game in William Lewis, Gioachino Greco on the Game of Chess (1819) and game XXV, variation A in Professor Louis Hoffmann [Angelo Lewis], The Games of Greco (1900). Hoffmann's game and variations appear in David Levy and Kevin O'Connell, Oxford Encyclopedia of Chess Games, Vol. 1 1485-1866 (1981). This version, sans the variations in Lewis and Hoffmann, appears in  ChessBase Mega 2020. Chessgames.com has Lewis's twenty-third game, instead of his variation A.

A longer version appears in Francis Beale, The Royall Art of Cheese-Play (1656). In Beale's version, Black's bishop first checks from b4 and then retreats to e7 after White's c-pawn blocks the check.

None of these books or databases offer the whole of Greco's analysis evident in his manuscripts. Both the extent of Greco's analysis and that which preceded his work becomes clear in "Part II. Openings and Games of the Classical Era of Modern Chess" (439-530) in Peter J. Monté, The Classical Era of Modern Chess (2014). I first mentioned this definitive work on Chess Skills with "Monumental Scholarship" (June 2020). Monté offers an analysis tree that ends every line with the names of sixteenth and seventeenth century manuscripts where these lines appear. He also references a few later published books, such as Beale, that are grounded in manuscripts.

Jon Edwards, Sacking the Citadel: The History, Theory and Practice of the Classic Bishop Sacrifice (2011) came into my possession a few days ago and provoked my interest in creating this article. Edwards attempts to give Greco his due, while acknowledging that Giulio Cesare Polerio may have "discovered it first" (8). He offers an admirable effort to present a more detailed biography of Greco and some context to place Greco in his times. Edwards draws on a number of Renaissance histories to construct his narrative. Unfortunately, he seems a little too trusting of dubious accounts and does not source his claims well. Some information is clearly grounded to a text, but mostly the author presents only a general bibliography of sources at the back of the book.

As Edwards tells it, Greco read Salvio's Trattato and Ruy Lopez's text, showed promise, and began studying with Don Mariano Marano (13-14). The claim that Greco studied under Marano derives from Richard Twiss, Chess (1787) and was repeated by Lewis in his book on Greco's games mentioned above (vii). Monté notes a number of historians who have expressed doubts concerning Twiss's claim. Salvio states only that Greco met Marano twice. Monté states, "an early acquaintance with Marano is based only on a rather vague suggestion by Salvio" (319).

That Greco was in Rome in 1619-1620 is better attested. No less than four extant Greco manuscripts exist from this time and indicate Greco's presence in Rome. Two of these manuscripts are undated and two are clearly dated early 1620. "[A]ll approximately dated facts of Greco's life are exclusively provided by his manuscripts", according to Monté (321).

Turning now to Monté's 90 page opening tree and documentation, we find variations containing the classic bishop sacrifice absent from the standard texts containing Greco's games (Beale, Lewis, and Hoffmann).

1.e4 e6 2.d4 c6

This strange move is absent from all modern references to Greco's games, but appears in three manuscripts of unknown authorship classified by Monté as part of the Lopez-complex: Elegantia, Regole, and Riccardiana (146, 156ff, 518). The idea is to bring Black's queen out with check. The check only occurs after White plays c4, a move recommended by Lucena.

3.Bd3 Be7 4.Nf3 Nf6 5.h4 Kg8&Re8

Castling, as we know it today, is older than Greco, but was not universally adopted. There were local variations. Some places there was a range of choices a player could make as to the squares where the king and rook ended up during the move. The placement of the rook on e8 makes the bishop sacrifice to come less forcing as Black's king has an additional option after accepting the sacrifice, as well as a second square for refusing.

6.e5 Nd5 7.Bxh7+ Kxh7 8.Ng5+

Black to move
The three main options 8...Bxg5, 8...Kg6, and 8...Kg8 all appear in Salvio's Trattato (1604). Greco adds additional lines or extends them. Because 8...Bxg5 has more variations, I begin with the other two.

a) 8...Kg6 9.h5+

Salvio ends here. Greco adds:

9...Kh6 10.Nxf7+ K moves 11.Nxd8 with these moves appearing in the Orsini (1620) and Lorraine (1621) manuscripts.

b) 8...Kg8 9.Qh5 Bxg5 10.hxg5

This line is in Salvio, Orsini, and Lorraine.

c) 8...Bxg5 hxg5+

And now, Black has 9...Kg6, 9...Kg8 appearing in Salvio and two Greco manuscripts. I will not present all of this analysis. You can find it in Monté's book, and it reappears in the games of others in the twentieth century. Here Edwards' analysis shines.

Noteworthy is 9...Kg6 10.Qh5+ Kf5 11.Qh3+ Kg6 (11...Ke4 12.Qd3#) 12.Qh7# in Salvio, and two early Greco MSS. For 11.Qh3+, see below.

Lines with 3...Nc6 instead of 3...c6 do not appear in Salvio, but appear in a larger number of Greco manuscripts, beginning with Mountstephen (1623), one of the London MSS.

Game 1 in Edwards, Sacking the Citadel appears in ChessBase Mega 2020, Lewis, and Hoffmann.

1.e4 e6 2.d4 Nf6 3.Bd3 Nc6 4.Nf3 Be7 5.h4 0-0 6.e5 Nd5 7.Bxh7+ Kxh7 8.Ng5+ Bxg5 9.hxg5+ Kg6 10.Qh5+ Kf5

White to move
11.Qh7+

Edwards comments, "Chernev was the first to mention a quicker checkmate with 11.Qh3+" (96). He does not indicate where Chernev offers this analysis. Nonetheless, the sequence appears in Salvio, as noted above, albeit with the difference that Black played 3...c6 instead of 3...Nc6.

11...g6 12.Qh3+ Ke4 13.Qd3# 1-0

It appears that Greco's early manuscripts are almost completely lifted from Salvio with respect to the French Defense and the classic bishop sacrifice. By 1623, however, Greco was developing his own ideas and adding variations.

Did Salvio, rather than Greco, first discover the Bxh7+ sacrifice? Perhaps not. In the Doazan manuscript, there may be an earlier version. The MS was sold in 1827 and then offered for sale again in 1841, In 1843, its new owner, Gabriel Eloy Doazan introduced it in an article in Le Palamède. When Doazan died in 1864, it was sold again and lost. The bulk of its contents were transcribed by Tassilo von der Lasa in 1855. It is from these transcriptions that we know much of its content.

Doazan dated the manuscript to 1600, but not much credence is given by historians to his claims.

The manuscript is of unknown authorship and date, but may reflect the work of Polerio and his associates. Some of the games are credited to other players. A line credited to Giovanni Domenico contains the classic bishop sacrifice.

1.e4 e6 2.d4 Nc6 3.Nf3 Be7 4.c3 Nf6 5.Bd3 O-O 6.h4 d5 7.e5 Ne8

White to move
8.Bxh7+ Kxh7 9.Ng5+ Bxg5 10.hxg5+

It appears that is as far as the game goes, but we know the possible conclusions.

Greco's games, especially if more of them were made available in databases, remain the most detailed early analysis of the classic bishop sacrifice. He copied lines from Salvio, and may have been exposed to ideas from even earlier. Greco developed these lines further. 



*Winter's question appeared in Kingpin (August 1996), and then again in Chess Notes 7979 "Greek Gift", which references the republication of the Kingpin column in Kings. Commoners, and Knaves (1999).

07 December 2015

Checkmate Patterns

The first thing for the reader to learn is to see every possible mate; this is one of the requirements of a good player.
Renaud and Kahn, The Art of the Checkmate
When David Weinstock recommended The Art of the Checkmate (1953) by Georges Renaud and Victor Kahn, I felt that he was underestimating my skill level. I met David when ChessMate, his company, was a vendor at the 1996 Washington Class Championships. It was my sixth USCF tournament and my first outside the Spokane area. Because I did not know anyone there and am an incurable bibliophile, I spent much of the time between rounds looking at the books ChessMate had available for sale and talking with David. He had several Chess Informants available for sale and he showed me how to read Informant codes. The Informants listed in the USCF sale catalog had piqued my interest. David answered questions, paving the way for my first Informant purchase a few months later (see "Playing by the Book").

I was in my mid-30s and had been pretty serious about chess as a teenager. In my youth I had learned how to checkmate efficiently with queen, rook, and two bishops. I had not mastered checkmate with bishop and knight, nor did I have a solid understanding of the two or three dozen most common checkmate patterns. Nonetheless, I thought that my checkmate skills were a strength as I could discover patterns when the opportunity was present.

In my first rated USCF tournament, I found the checkmate in two from this position.

White to move

My confidence in my ability to checkmate could be backed up with evidence from my games. I had been playing chess for more than two decades before entering rated competition. My transition from clueless beginner to capable novice took place during the rapid improvement that followed from learning to read chess books (see "My First Chess Book"). I developed an aggressive playing style grounded in attacking the king.

Surely there were other weaknesses in my game that should be addressed. Indeed, when I look at those old games now, I see terrible opening moves, egregious middlegame blunders, embarrassing endgame technique and even a few missed checkmates.

Nonetheless, when I saw The Art of the Checkmate in a bookstore a few years later, I pulled it off the shelf and looked inside. It was not the book that I had imagined when David Weinstock first suggested it to me. I bought it and started reading. Within a few weeks, I was checkmating my opponents on the Internet Chess Club with new patterns, such as in the game below.*

Internet Opponent (1415) -- Stripes,J (1439) [A45]
ICC 5 0 Internet Chess Club, 03.04.2001

1.d4 c5 2.dxc5 Nf6 3.Bg5 e6 4.c3 Bxc5 5.Nf3

Black to move

5...Ne4 6.Bxd8??

6.Be3 was necessary.

6...Bxf2# 0–1

I began to appreciate the quality of David's advice. The Art of the Checkmate is a terrific book. Renaud and Kahn not only present checkmate patterns that I had not known, or did not know as well as I thought, but much more.

Renaud and Kahn present whole games well-analyzed. They show how positional errors create the conditions for checkmate combinations. They develop each pattern from the basic pattern to more sophisticated examples, and then to the pattern as a threat designed to force positional concessions. The Art of the Checkmate is a simple book, but not quite as simple as I imagined.

The first checkmate pattern presented is dubbed Legal's Pseudo-Sacrifice by the authors, The chapter on this pattern contains seventeen games and not all are king's pawn openings. Some games end in the checkmate pattern, but others lead only to a modest gain of material or positional advantage for the side employing the pattern. Nor does White always prevail.

When I read this book some fifteen years ago, one of the variations presented in the notes to the seventh game stuck with me.

1.e4 e5 2.Nf3 Nc6 3.Bc4 d6 4.Nc3 Bg4 5.h3 Bh5 6.Nxe5!

Black to move

Among the games preserved in my database, I've had White in this position ten times. Only once did my opponent play 6...Bxd1 and fall for Legal's Mate. Renaud and Kahn's note suggested that 6...Nxe5 is the "lesser evil" (15).

Play then continues 7.Qxh5 Nxc4 8.Qb5+.

I have had the resulting position in seven of those ten games, twice against one opponent. I have won five of those game. I have also faced 6...dxe5 (I won) and 7...Nf6 (I won). Playing the recommended moves has given me an 80% score from the diagram position even though my opponents do not fall for the queen sacrifice (Legal's pseudo-sacrifice).


*I had been exposed to many of these new patterns in my first chess book, but the intervening decades had erased many details from my memory while leaving general impressions.