Wednesday, September 21, 2016

TPS Report #19

I came into possession of a talisman, a touchstone that symbolizes my relationship with movies, with computer programming, and with rebelling against authority. Yes, I now have a red Swingline stapler similar to Milton's of "Office Space". I even filled it with staples even though I almost never staple things together at my desk. But I could, and that's what's important. Perhaps I will print these 19 TPS Reports, collate them into a stack, attach a cover sheet AND a memo, and staple the whole mess together, just for the fun of it. A strange sort of cognitive dissonance comes from watching myself imbue this inanimate object with magical properties. Why does such a mundane thing make me happy?

I have not been playing chess, but I have been going over my opening repertoire. I have not been training middle game tactics, but I have been annotating rook and pawn endgames. I have not been studying the games of masters, but I have been watching some broadcasts from the St. Louis Chess Club. I have not been going to the chess club, but I have been blogging about chess. It's like I am of two minds: one that is attracted by chess, and one that is repelled. Autumn tends to strengthen the pull of the chessboard on me. But I actively resist some of its basic trappings.

In tracking where my blog referrals were coming from, I found out that my old friend Temposchlucker started blogging again at the end of 2015 and went strong through every month in 2016, until August when his blog went dark again, temporarily or not. A key question seemed to awaken his passion for analysis: How does one see the invisible? Sometimes, I am surprised at what I see. It is as if my mind sees without the participation or consent of my conscious will. Neural networks, like the one used to beat the Go champion, use nodes to needle the network into producing an integrated result. Somewhere, I have neurons that fire faster when pieces are knight forks apart or related by bishop and rook pins. How do those neurons get their programming? Will Tempo or the knights or anyone else find that thing that trains the eye to see what it doesn't see?

I was somewhat inspired by the volumes of words produced by Temposchlucker and by another blogger on the "Path To Chess Mastery". But in the end, the proof is in the pudding. Can I train myself to be as good as a master? Is that even my goal any more? It is a question that seems more likely to be answered in the negative given my emotional momentum. A rejuvenation of my commitment to a younger man's goals seems unlikely. The expression is usually "Time will tell," but I wonder if it is more accurate to say "Time may or may not tell."

Tuesday, September 20, 2016

Practical Rook Endgames 16: Sack the Waterboy

The 1998 Adam Sandler football movie "The Waterboy" ended with a halfback option play. Sandler, the lowly waterboy turned punishing linebacker switches to offense and throws the winning touchdown pass to the quarterback. Sorry I spoiled it, but you had 17 years to watch it.

Theoretical generalizations seem to say that R2P versus R endings with a bishop and a rook pawn are drawn if the pawns are on the same side of the board and won if the pawns are on opposite sides of the board. After a seesaw game, I had the stronger side of the same-side ending but managed to find a way to win. This depended upon my opponent choosing the wrong time to ignore the weakness of my bishop pawn. I'm barely scratching the surface of this ending, but I thought I would share this position and its critical moment:

For the purposes of the Waterboy analogy, the f-pawn is the waterboy, the white king is the offensive quarterback, the white rook is the center or offensive line, and the black rook is the pass rush. White has just played 67.Rf6, so it's Black to move. I'm not sure why I put my rook on f6, but I think that I wanted my king to be able to lose contact with the f-pawn. My plan here was to move my king to e7 and perhaps block a Re1+ with Re6 and then try to queen the pawn. 67...Rg1+ 68.Kf4 Rf1+ 69.Ke5 Re1+ 70.Kd6.

Black to move. Here Black has to decide whether to chase the king further with 70...Rd1+ and live with 71.Ke7 or prepare some other way to get drawing chances. Actually, Rd1+ is still drawn and my opponent's choice is still okay to draw. 70...Ra1. Preparing lateral checks. The white king at this moment has no shelter from checks on the 6th, 7th, or 8th ranks. So I decided to create shelter. 71.Re6.

Black to move and draw. A critical moment has arrived. The two moves that can draw are slightly difficult to spot. 71...Ra5 and 71...Rf1 maintain tablebase draws. All other moves lose. Sample lines are: 71...Ra5 72.Re5 Ra4 73.f6 Kxh6 74.Ke7 Kg6= and 71...Rf1 72.f6 Kxh6! 73.Ke7 Kg6! 74.Re2 Ra1/b1! with lateral checks to hold. Unfortunately for my opponent, he didn't recognize that it was time to sack the waterboy. Instead, he followed my quarterback downfield to where I wanted to receive the Hail Mary pass and queen the f-pawn. The remaining positions are all tablebase wins for White. 71...Ra6+?? 72.Ke7! Ra7+ 73.Kf8! Ra5 74.f6! Ra8+ 75.Re8! Ra6 76.f7 Kxh6 Kg8! and Black resigned.

Saturday, September 17, 2016

Practical Rook Endgames 15: Vancura Caveats

Isaac Asimov's short story collection "I, Robot" was made into a 2004 movie starring Will Smith as Detective Spooner. I love the writing in spots and wish to highlight two segments: 1. Dr. Alfred Lanning's soliloquy in the middle of the movie which I have quoted in brief before:

There have always been ghosts in the machine. Random segments of code, that have grouped together to form unexpected protocols. Unanticipated, these free radicals engender questions of free will, creativity, and even the nature of what we might call the soul. Why is it that when some robots are left in darkness, they will seek out the light? Why is it that when robots are stored in an empty space, they will group together, rather than stand alone? How do we explain this behavior? Random segments of code? Or is it something more? When does a perceptual schematic become consciousness? When does a difference engine become the search for truth? When does a personality simulation become the bitter mote... of a soul?

The second passage is near the beginning when Detective Spooner compares his task to Hansel and Gretel:

SUSAN CALVIN: I don't understand. Alfred wrote the Three Laws. Why would he build a robot that could break them?
DETECTIVE SPOONER: Hansel and Gretel.
SUSAN CALVIN: What?
DETECTIVE SPOONER: Two kids, lost in the forest. Leave behind a trail of bread crumbs.
SUSAN CALVIN: Why?
DETECTIVE SPOONER: To find their way home. How the hell did you grow up without reading Hansel and Gretel?

It's obvious to me that I really have a lot to learn about rook endings. The more I learn, the less I know. I didn't give any variations in my previous post because I thought that the Vancura was a shortcut to understanding how to draw the ending like an automaton. "Put your king on g7 and your rook on f6 and check, check, check your way to a draw." My one active reader commented and gave me a Vancura variation to chew on:

Black to move and draw. Since I am too lazy to work all the secrets out myself, I went straight to my favorite 6-man tablebase robot at the Shredder site and plugged in this position. I was surprised to find out that the path to a draw, far from a mindless template, was a bit more complicated. Actually, there are only two bread crumb trails that draw: A) Ra5 and B) Rc1. A) 1...Ra5 2.Ke4:

Here again, only two moves draw, but the pathways are convergent: C) 2...Rb5 3.Kd4 Rb6! (only move) and Black can look forward to moving his rook to f6 and checking until the draw comes home. D) 2...Rc5 3.Kd4 Rc6! (only move) with a similar Vancura pattern.

Going back to the previous diagram, here is the alternate way to draw: B) 1...Rc1 2.Ke5 Rc6! (only move) and we're back to familiar territory. Staying with the first diagram, I began the search for hypotheticals. Why doesn't 1...Rf1+ work?:

White to move and win. 2.Ke5! keeps White's winning path alive. Why can't Black just force the Vancura? It's tactically unsound here: 2...Rf6? 3.Rg8+! Kf7 4.Rf8+! The rooks come off and the a-pawn waltzes in. After Kf4-e5, if only Black could play Rf1-b6 or Rf1-c6, he would be on the true Vancura path. Let's try 2...Rf7.

White can still win. Shredder shows 5 moves to victory. The simplest is the pawn advance 3.a7. Black's rook is misplaced at f7. For the rook pawn on the seventh, the defender should be behind the pawn to prevent the attacker from just sacrificing his rook e.g. 3...Re7+ 4.Rd6 Rf7 5.Rg8+ Kxg8 6.a8=Q+. Continuing this White win variation, what if after 1...Rf1+? 2.Ke5 Black tries to draw with a spate of spite checks? White makes his way to sanctuary at a7 3...Re1+ 4.Kd5 Rd1+ 5.Kc5 Rc1+ 6.Kb6 Rb1+ 7.Ka7. With the defending king so far away, White reshuffles his rook to b8, king to a8, pawn to a7, then the White king moves out through b7, chases down the checking rook, and queens the pawn.

Going back to the beginning, I now asked Shredder, why does 1...Rb1? lose? Can't Black force Rb6 and find the way home?:

White to move and win. Shredder points out an unintuitive variation starting with 2.Ra7+!. White easily wins if Black goes to the eighth rank e.g. 2...Kg8 3.Rb7 Ra1 4.a7 followed by Rb8+ and a8=Q. 2...Kf6 is more testing. Now White has to avoid the drawing 3.Rb7? Ra1 4.Rb6+ Ke7!= but instead find 3.Ke4! Ke6 4.Ra8! It looks like White is going back to a previous position, but with the Black king away from his safe base of g7, more tactical checks come into play for White. I just realized that doing the shuffle is not always straightforward either and I'll probably have to devote a short post to the a6 pawn win.

Why didn't this Ra7+ win work against B) 1...Rc1!=?:

Black to move and draw. Now Black has to find three narrow bread crumb trails E) 2...Kg6!= 3.Ra8 Kg7!= and F) 2...Kg6!= 3.Ke5 Rc6!= and G) 2...Kg6!= 3.Rb7 Rc5!= angling back toward the classic Vancura with Kg7 and Rf6. As you can see, the path with A) 1...Ra5 is much safer than B) 1...Rc1. Here is one more argument in A)'s favor:

Black to move and draw. This diagram has one subtle difference with the first one. The White king is now at f5. Black cannot draw now with 1...Rc1? because 2.Ra7+! Kh6 leaves his king just too far away to prevent the brute force plan of White moving his king to b8 and escorting the pawn in. 3.Rd7 Rc5+ 4.Ke6 Rc6+ 5.Rd6 Rc5 6.Kd7+. Instead, Plan A) still works against Kf5: 1...Ra5+! 2.Ke6 Rh5!. I know that I warned in the last post not to put the Black rook behind the Black king, but here it is necessary. 3.Ra7+ Kg8!=. 3...Kh8? and 3...Kf8 both lose to 4.Rf7! blocking the Rh6+ skewer. Black also has to know that after 3.Kd7 there's still time to get back to Vancura with 3...Rh6! 4.Kc7 Rf6! and Black is ready with checks even if 5.a7 Rf7+!=. 5.a7 Ra6? loses to 6.Kb7! Ra1 7.Rb8.

From the attacker's point of view, getting the king to e4 or e5 while the Black rook is on a1 wins even if Black is on move. With White on move from the last diagram, 1.Ke4 or 1.Ke5 lead to wins. Surprisingly, 1.Ke6? only draws if Black can find .1...Rh1!=. From the defender's point of view, his rook must be on a5 prior to White getting from the kingside to Ke4 or Ke5. From Shredder, I see now that if White can get Kd4 and Black has not gotten his rook to b6 or f6 (e.g. he still has his rook on a1 or a5), then Black is lost. So the speed at which Black can get the ideal setup with rook on f6 or b6 is crucial.

Whew! As my reader commented "The theory of rook + a-pawn versus rook is actually surprisingly deep, with lots of different techniques."

Sunday, September 11, 2016

Practical Rook Endgames 14: Vancura Candidate

"The Manchurian Candidate" was first a book in 1959 written by James Condon. It was made into a black and white movie in 1962 starring Laurence Harvey as war hero Raymond Harvey, Frank Sinatra as his superior officer Bennett Marco, and Angela Lansbury as Shaw's mother Eleanor Iselin. The plot revolves around a Communist ploy to brainwash American POWs of the Korean War and turn them into subconscious sleeper agents in a bid to seize the United States presidency. The brainwashing occurs in Manchuria. Angela Lansbury, who I know as a sweet old woman of the "Murder, She Wrote" TV series and the voice of the animated teapot in Disney's "Beauty and the Beast," really shocked me with her range as a vicious and conscious sleeper agent earlier in her acting career.

Down the cast list is Leslie Parrish who plays Shaw's love interest Jocelyn Jordan. She appears in the middle of the movie to demonstrate the significance of the Queen of Diamonds and how firmly held the brainwashing control is on Shaw. Leslie Parrish makes several intersections with my cultural life: She appears in the original series Star Trek episode "Who Mourns for Adonais?" as a crew member who beguiles the Greek god Apollo. Leslie Parrish also figures prominently in Richard Bach's love story novel "The Bridge Across Forever." During their romance, they play chess together and she eventually becomes his wife in real life. Unfortunately, the soulmate subject of the book is somewhat invalidated by the fact that the two eventually separated.

"The Manchurian Candidate" was remade in 2004 starring Liev Schrieber as Raymond Shaw, Denzel Washington as Ben Marco, Meryl Streep as Eleanor Shaw, and Vera Farmiga as Jocelyne Jordan.

Whenever I try to remember the gist of the Vancura position, I feel like I have been brainwashed. It just doesn't stick. This morning, I listened to a lecture given by GM Alexander Ipatov on the Vancura position and for now, I have some memory stickiness. Interestingly, Ipatov pronounces it "van-chur-a" while I always thought it was "van-cure-a". Ipatov introduces the position with this diagram:

The elements of Vancura are the following:

  • Material is RPvR.
  • The pawn is a rook pawn, specifically on its 6th rank, not 7th.
  • The attacking rook is usually on the rook pawn's queening square.
  • The defending king is on the opposite side of the board, preferably on his knight-2 or rook-2 square.
  • Vancura's classic position has the defending king on g7 and the defending rook on f6.
  • The attacking king is not yet touching the rook pawn.

Black's formulaic method to draw is to Plan A) check the enemy king from the f-file, especially when it touches the rook pawn, or Plan B) shuffle his rook between b6, c6, and f6 when Plan A does not seem viable. If the pawn ever goes to a7, then the black rook belongs on the a-file and the black king must stay at g7-h7. One caveat: Don't put the rook where it will run into your king on the g-file or get behind your king on the h-file. Other than dropping a rook or forgetting to check the king when it touches the pawn, drawing this ending doesn't seem too hard. The attacking rook should never leave the a-file because the a-pawn will immediately drop. The defending king should stay in contact with the square h7 so that the attacking rook can't skewer. Sometimes, the rook will check Ra7+. The king just moves to g6 or h6.

The reason this formation needs extra significance is that the weaker side can't always leave his rook on the a-file and draw, especially if the stronger king can make it to a7. If the pawn moves to a7 and the king moves to a8, then the weaker side has to run his king toward the a-pawn before the attacker can set up the winning formation with Rb8, Kb7, and Pa7. With Vancura, the defender earmarks the f-file for his rook to harass the enemy king from afar. There is basically nowhere to hide.

This method can probably be extended to the situation where the rook pawn is only on the fifth rank, possibly even earlier. This method also works to draw against an extra g- or h-pawn held by the attacker. The defender must be careful that he doesn't allow a free check with Rg8+ or something, so sometimes the extra pawn sits en prise at g5 or h5 with the defending rook just shuffling around.

Karsten Mueller wrote an article about Vancura after the 2014 Sinquefield Cup game between Carlsen and Aronian, quoting some spectator as saying "It is insulting that Aronian is not resigning." But Aronian used Vancura-like methods to get a difficult draw three pawns down. Carlsen's extra pawns were at a5, h6, and h3.