25 August 2022

En Passant

One of my students requested a lesson on en passant, so I created one. We did not need to go over the rule as he had shown that he understands that much. So, what was I to do? The first position that came to mind was the game that provides the position for the banner at the top of the page. This game was a 3 0 blitz game that finished in under two minutes. I played it on my iPad while waiting for my lunch in the Classic Cafe in Deer Park, Washington. I had spent a couple of hours in the morning teaching chess at a homeschool resource center and had another couple of hours teaching chess in classrooms at Deer Park Elementary. I recall showing the game to the students that afternoon because it illustrated en passant and checkmate, two vital rules beginners need to learn.

White to move
Black played 13...f5+. An en passant capture is White's only legal move. 14.exf6 and then the d-pawn advanced with checkmate. It was a memorable game with errors on both sides, but some interesting tactics that have instructive value.

I followed this position with a couple from Roman Pelts and Lev Alburt, Comprehensive Chess Course, vols. I and II (1986). Then some mates in one culled from several sources. The student blazed through these very quickly. We then spent a couple of minutes on his successful effort to find the moves that had to be played to reach this position, which appears both in Ilya Maizelis, The Soviet Chess Primer (2014) and in Pelts and Alburt.

Black to move
I found two short games in the Lichess forums that were composed in answer to the question: what is the shortest possible game that ends via checkmate with an en passant capture? Both White and Black are able to checkmate in this manner on the sixth move.

We finished with an endgame exercise and a mate in four that I composed an hour before the lesson.

White to move and win

White mates in four




24 August 2022

Stalemate

This morning in a desperate position I "blundered" away a rook. My opponent fell for the ruse.

White to move
I played 53.Ra1 after which Black wins easily with 53...Nd4+ and taking the rook the next move. However, 53...Rxa1 fails to win, as my opponent learned after ending the game with that move.

A search of my online games database shows nearly 1100 games that have ended in stalemate. A portion of these were provoked in the manner of this morning's offer of a rook, and were preventable. 

This position arose on the Internet Chess Club in 1999. Black to move.

Black to move
I played 65...Rd5+ and my opponent took the rook. If they would have played Ke6, the next check could be met with Kf7. The engine needs some depth to realize that White's king has no shelter from the rook's sacrificial efforts. White's 65.Bf5 was the error that led to this position. The bishop had been on g4. 65.Re8+ would have eliminated the stalemate prospects.

Something similar and simpler arose in an OTB game in 2006.

White to move
My opponent played 54.h7?? Naturally I played 54...Rxb7 and we agreed to a draw after I took the other pawn, too.

And again in 2000 on ICC.

White to move
55.a7+?? allowed me to start checking with my rook. 55.Ka8 56.Ka5 Ra1+ 57.Kb6 Ra6+ 58.Kxa6. White has some work to do to win this ending, but pushing the pawn made Black's efforts simple.

This position arose more than two decades ago on the Internet Chess Club.

Black to move
I threw away the win with 55...Rg2. My opponent forced stalemate.

Even worse on my part was this position five months later.

Black to move
56...Bf8 leads to checkmate on the following move, but I played 56...Be5. No effort was needed by my opponent, except the stubborn refusal to resign in a hopelessly lost position.

No stalemate threats seem evident in this position from a five minute game.

Black to move
Nonetheless, 45...Kg4 surrendered the win. 46.Rxe5 f3 47.Re4+ Kf5 48.Rb4 h2+ 49.Kh1 and now White will try to eliminate his rook and succeeded another dozen moves later.

Black could have played 45...f3 and then used the e-pawn as shelter from rear checks.

I did not suspect this opponent of cheating, but he was banned a few hours after we played on Chess.com yesterday. 

White to move
As a final act of desperation, I played 55.a5. My opponent obliged with 55...bxa5 when 55...b5 would have won. I offered a draw. He refused. I told him it was a dead draw. He replied that he did not agree. We played until stalemate.

However, I have suspicions about my opponent in a game that reached this position.

White to move
42.Rd6+

Although inferior to 42.Rc1+, White has so far kept the win in hand.

42...Kc5 43.Rxe6 Kd4 44.Rxb6

Grabbing pawns seems sensible if you are not skilled and have turned off the engine because you are confident of securing victory on your own. I began to maneuver for the opportunity to swindle half a point. 

45.e6 Kxf4 46.e7 Rxe7 47.Ra6 Kg3!

White to move
48.Rxa5?!

48.Rf1 Rd7 49.Rf3#

48...Re2 49.Rxf5??

49.Rf1 still wins.

49...Re1+

Stalemate is forced in two moves. I was surprised how easy it was to swindle this player.









20 August 2022

The Wrong Move

Several days ago I was watching a recent PowerPlay video by Danny King. He featured a game that had an impact on the final standings at the Chess Olympiad in Chennai: Muzychuk,M. -- Kashlinskaya,A. After 27.Qd6+, black faced two possible legal moves.

Black to move
The safer looking move, which was played in the game, was the wrong move. It was the "losing" move, according to King.

Later that day, I was reading a book that had recently arrived: Jacob Aagaard, A Matter of Endgame Technique (2022). The first exercise at the beginning of the first chapter takes a position from Concio,M. -- Tin, Jingyao, 2021 played online in an Interzonal qualifier for the 2021 World Cup. Again, Black has two legal moves.

Black to move
Again, the move played in the game, and the one I might have chosen on impulse, was the wrong move. With Aagaard's book, however, I knew it was wrong, but failed to find the reason. Reading the book made it clear that I needed to calculate more deeply.

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

04 August 2022

King Safety

Working through the games in Kevin Wicker, 200 Modern Brilliancies (1981), I came upon this mess from a postal game between Toni Cipolli and Semen Gubnitsky played in 1977.

White to move
Cipollini did not find the right idea. Nor did Wicker.