Saturday, October 3, 2009

a few tactics from today's scholastic tournament

Lequasiah Lawrence went 4-0 and won the reserve section. Her fourth round game reached the following position:

Lequaisiah's white. Do any of her attacking tries (9. Nf6, 9. Qg4, 9. Qh5, 9. Bxh6) work? Which is best?




same game. White to move?


Henry Cali's last move, 7. Bc4, was a mistake.
Where should his opponent (black) have moved?
His opponent actually played 7... Qd8. How does that lose tactically?
Does 7... Qd6 lose to the same tactic?

Sebastian Dabrowski won his first three games before losing to 3rd place finisher and 318 alumnus Rochelle Ballantyne. What classic tactic did Sebastian (white) find against (also 318 alum!) Ezequiel Quinones?


12 comments:

Anonymous said...

1st position. White's problem is that the h7 knight is trapped, e5 is hanging, and Black can play Ng6 to stop mating threats. I don't see a win for White. Probably the best practical chance is 1.Qh5.

2nd position. White would like to capture the enemy queen, but unfortunately the knight is pinned against the back rank mate. This suggests something like 1.Bxh6, which defends e1, and thus "arms" the threat to the Black queen. If 1...Qd7, then 2.Bxg7+ looks decisive.

3rd position. I don't see anything better than 1...Qe4+ 2.Be2 Bxf3 3.gxf3, leaving White with weak pawns. 1...Qd8? is a mistake because it allows 2.Bxf7+ (2...Kxf7 3.Ng5+ followed by 4.Qxg4) winning a pawn. 1...Qd6 is different because Black threatens the tactic Qe5+, winning the rook on a1.

4th position. As soon as you said "classic," I thought of 1.Re8+!

anjiaoshi said...

In position 2, 1.Bxh6 threatens mate if 1...gxh6 2.Qf7#. So black has to play 1...g6, which trashes white's attack.

1.Ng5+ followed by 1...Kh8 2.Nf7+ frees white up to play 3.Bg5, which clears the back-rank problem with tempo. If 1...Kg8, 2.Rxe8 Qxe8 3.Qf7+ forces an exchange of queens.

Playing 1.Bg5 first doesn't seem to accomplish much. Black's queen is safe on d8, and the white knight can't get to its best attacking square.

Anonymous said...

In position 2, after 1.Bxh6 g6 2.Ng5+ Kg8 3.Qf3! white wins, e.g., Bf5 4.Rxe8+ Qxe8 5.Qxd5+ winning a piece.

Anonymous said...

I wonder if the P Style comes in Magenta or Aquamarine.

Bill Brock said...

Position 3 & suggested variations is a very nice "real life tactics" exercise. Note that 1...Qe4+ doesn't just spoil White's pawn structure, it also wins a button.

White is indeed in trouble in position 1; I suspect 1.Bxh6 (develop!) is the best practical chance.

gurdonark said...

Those were all fun!

Elizabeth Vicary said...

1. She played 10. Qg4, but this is just bad because of 10… Nxe5. Going over the game, I thought 10. Nf6 was practically winning: 10… gxf6 11. Qg4+ Ng6 12. Bxg6 fxg6 13. Qxg6 Kh8 14. Qxh6 Kg8 15. Qg6 Kh8 16. exf6 or 11… Kh8 12. Bxh6. Practically, it is winning, but in a perfect world black has two defenses. In the first line, 12… Nxe5 saves black, and in the second, black is actually already ok with perfect defense: 12… Ng6 13. Qh5 Ncxe5. 10. Qh5 is also great -- of course fritz can defend, but no kid will find a good way to deal with the threat of 11. Bxh6. 10. Bxh6 seems a little less dangerous to me?

2. In the later position, 1. Bxh6 is totally winning: if 1… gxh6 2. Qf7-g7 = mate.

3. Black should have played 7… Qe4+ 8. Qe2 Bxf3 9. gxf3 Qxc2, winning a pawn. After 7… Qd8, white could win a pawn with 8. Bxf7+ Kxf7 9. Ng5+ and 10. Qxg4. After 7… Qd6 this doesn’t work because black has 10… Qe5+, winning the Ra1.

4. Black blundered with his last move … Qd6, which loses to Re8+.

Bill Brock said...

Strangely, 10.Qg4 is not bad because of 10...Nxe5. 11.Nf6+! Kh8 (only try: 11...Kf8 12.Nh7+ Kg8 13.Nf6+ repeats) 12.Qh5! and White will get the Exchange as partial compensation for the lost pawns.

But the ...Nex5 idea is winning in the right order: 10....Ng6! 11.Bxg6 Ne5!

Re 10.Nf6+: your line ending in 12...Nxe5 doesn't just save Black, but is winning for Black.

10.Bxh6 gxh6 11.Nf6+ Kg7 12.Re1! and White has some cheap play: for example, 12...Rh8 13.Qf3 (idea Nh5+) and of course Black is better but not clearly winning.

Today I cheated with Rybka....

Bill Brock said...

Hmm, maybe 10.Qh5 *is* stronger. 10...Nf5 seems natural enough for a kid to find (fortifies h6 and threatens h7) 11.Bxf5 exf5 12.Bxh6 and now 12...Nxe5! with the idea 13...Ng6 & 14...Qh4 is thematic...but maybe harder for kids & grownups to find.

gurdonark said...

to change the subject a bit, have you seen this homophone alternative website?

http://www.lizzievickery.com/main.php

Anonymous said...

Manly men who daily take excretory flight
Equipped at birth to eschew the hollow'd seat they
Do not go squatting when the bladder's tight.
Stand, stand and take relief from a height.

P Style. Get it in fuchsia.

Elizabeth Vicary said...

Beautiful poem, thank you. Sadly you cannot choose the color of your P style. I do not know why.

There’s a great discussion at
http://usclnews.blogspot.com/2009/10/week-5-game-of-week.html