|
|
dimis
Responsible
Supreme Hero
Digitally signed by FoG
|
posted November 29, 2009 11:42 AM |
|
|
Thanks ihor!
____________
The empty set
|
|
ohforfsake
Promising
Legendary Hero
Initiate
|
posted November 29, 2009 02:35 PM |
|
|
It's very impressive and it reminds me when we had an event, where I think we were 60-80 people, playing against the best person of Denmark, though it had nothing to do with blind chess, he won all except 2 which he played draw, but you could also see he did his homework.
Against the good players of the opposition (I think he'd 2600 and the best on the other side about 2200-2300) you could see he used a lot more time against those people, against weaklings like me, he quickly took a look and moved.
Those he played draw with had merely 1400-1600 rating, so he probably went too fast against those (one he offered the draw, the other he ended up in and eternal check position).
____________
Living time backwards
|
|
ihor
Supreme Hero
Accidental Hero
|
|
posted November 29, 2009 02:36 PM |
|
|
Oh, its nothing!
I've only just found Keldorn's last puzzle. It is indeed obvious. HCM sent.
|
|
ohforfsake
Promising
Legendary Hero
Initiate
|
|
posted November 29, 2009 02:45 PM |
|
|
I thought about it, assuming you and I have the same solution, I have a huntch it might end in a draw anyway, because it might end up with two pawns all in the corner, and black the keeping its pawn on the black square and can't be forced away via waiting moves, though I'm not certain.
____________
Living time backwards
|
|
ihor
Supreme Hero
Accidental Hero
|
|
posted November 29, 2009 02:46 PM |
|
Edited by ihor at 14:49, 29 Nov 2009.
|
I also remember when I was younger I played in tournaments, but that was inglorious  . Now I should say thanks to Keldorn because after his reviving of this thread I returned to this beautiful game after 2 years of break. Although I'm relatively weak player, it's always fun, recently played with my classmates and relatives.
Edit: 1min difference second time . I also thought about draw, but obviously it is not required in this puzzle.
|
|
ohforfsake
Promising
Legendary Hero
Initiate
|
|
posted November 29, 2009 03:07 PM |
|
|
Quote:
I also thought about draw, but obviously it is not required in this puzzle.
You're probably right, it's just that for me, every puzzle should be looked at like a board game, at least in the purpose of winning, then the question is, what move gives you the best odds of winning, so in that sense, it doesn't matter if you can win 8 queens from the opposition if by winning the knight will win you the game at much higher likelyness.
Of course likelyness is based on information, and in this game, information is how far ahead you can see (how much time you give to it), and in that sense, you're probably right that the idea of the puzzle is to what I think both of us have done.
|
|
keldorn
Promising
Known Hero
that casts green flames
|
|
posted November 30, 2009 02:50 PM |
|
Edited by keldorn at 14:53, 30 Nov 2009.
|
I'm glad to welcome you in the world of chess Ihor  . BTW, the hungarian master you wrote about is Fless János.
Yesterday I had an idea and decided to share it with you. I'm sure you know that I'm preparing another quiz, so by the time it's ready, I'd like to start a competition.
Your task is to compose some puzzles, similar to those I've shown you recently. Just choose one or more tags (pin, fork, mate etc.) and set up a position where one side can win by using the above trick(s). Please note that this is not a puzzle-collecting competition. Cheaters will be banned .
You can post your puzzles here so that others can solve them. The most beautifully-executed trick will win. This, of course, doesn't necessarily mean that the longest move sequence wins automatically.
If you're interested, you can begin composing. I'll send my quiz on Friday again, so that will be the end of this competition. And while you're solving my quiz, I'll check your puzzles. Please be sure to think twice before posting your compositions: if I find a good defense for the losing side that neutralizes your tactics, that apparent puzzle will be considered wrong. Have fun
EDIT: I almost forgot one thing. You can send more than one compositions. The more you send, the better chances you have, but all puzzles must be your own.
____________
|
|
ihor
Supreme Hero
Accidental Hero
|
|
posted December 03, 2009 07:54 AM |
|
|
If nobody posts puzzles, I'll post one. I know it sucks but doesn't matter . White to move and win material.
This was a bit modificated from real game.
|
|
ihor
Supreme Hero
Accidental Hero
|
|
posted December 04, 2009 07:40 AM |
|
Edited by ihor at 07:40, 04 Dec 2009.
|
It seems the puzzle is wrong. Sorry to all who wasted time.
OFFS found countermessure.
On the planning move of whites c5 black could counter Bf4 and the pinned black queen could be changed by white one. Everything stays equally. I apologize.
As I said earlier I suck at creating puzzles.
____________
Your advertisement could be
here only for 100$ per day.
|
|
keldorn
Promising
Known Hero
that casts green flames
|
|
posted December 05, 2009 01:49 PM |
|
Edited by keldorn at 13:52, 05 Dec 2009.
|
Sorry for being late guys, I had some things to do tghis week, but the quiz is ready finally. Enjoy.
I. Mate in X
II. Winning material
III. Openings
IV. Positional play
V. -NEW TOPIC- Endgames
And of course the +I. Bonus questions
Please note that these puzzles are based on what we've learned from the previous +I. topic. Feel free to go back and study the problems there.
1) Game reproduction: Again, you're both white and black. The only condition: The game onds on move 5 with a mate, when one side gives checkmate to the other via an underpromotion to Knight. What's the game (5 move pairs)?
2) In the position below, the white king is removed from the board. Where was it? Give me the logic: why did you choose your square?
You know the rules . Good luck and have fun.
____________
|
|
ihor
Supreme Hero
Accidental Hero
|
|
posted December 07, 2009 08:43 AM |
|
|
|
keldorn
Promising
Known Hero
that casts green flames
|
|
posted December 07, 2009 03:36 PM |
|
|
Well, Saturday? Then I'll have time to check your work on Sunday.
____________
|
|
keldorn
Promising
Known Hero
that casts green flames
|
|
posted December 13, 2009 01:26 PM |
|
|
Sunday has come so it's time for me to reveal the solutions and scores. Here we go.
I. Mate in X
A) 1.Nf6+ is a double check, so ...Kh8 is forced. 2.Qg8+!! Rxg8 again forced. The king can't take due to our knight on f6. 3.Nf7# smothered mate. (2 points)
B) 1.Kf6! Kh8 forced. 2.Kg6#. It's interesting that only the two kings move during the process. (2 points)
C) 1.Qg5+! fxg5 forced. Now black has but one legal move which is ...g2. This opens up the third rank, so white exploits this by 2.Ra3!. Now ...g2 forced, 3.Rh3# (3 points)
D(!!) The key to this problem is to notice that black is almost stalemated. White's goal is to get the Queen to a more active square to give mate so we start with 1. Qf7 d2 (notice that all of black's moves are the only legal moves in that position) 2.Re4! fxe4 3.Qxe4 Nf5 4.Qxf3+ Kh4 5. Qf2+ with mate to follow (...Ng3 is just a spite move, 6.Qxg3#) (4 points)
Here Ecoris found out the correct idea, but made a little oversight on move 4, resulting in a wrong first move. 1.Rb4 fails to ...d2(forced) 2.Rb5 cxd5(forced) 3.Qe7 b4 (good thinking up to this point ->1.5 points) 4.Qe2 and now ...Kxf4! escapes. I recommend to set up a board at home with this position and go through my solution, and even through Ecoris' if you want to make sure you understand everything.
II. Winning material
A) White is threatening mate in 3 with his doubled rooks via 1.Rg7+ Kh8 2.Rh7+ Kg8 3.Rag7# but this is defended by the black Queen. So 1.Qb3+! removes it with tempo (check). Black can't take, so Kf8 is forced, then 2.Qxb2 and black is threatened with mate, so he has to move the Rook from f8 to give the king an escape square, so white emerges a Queen ahead. (2 points)
Ihor's solution (1 point) is also acceptable, but wins only a rook instead of a Queen.
B) 1.Bxa6! pins the Queen so ...Qxa6 is forced. But this leaves the e7-rook unguarded against 2.Qxe7. (2 points)
C) 1.Bd3 covers the king's only escape square and also opens up the a-file for white's rook. White threatens mate with two pieces, one of which also threatens a rook, which is immune du to mate. Black can't defend these threats. Best is ...Nxd3 to remove the bishop's attack on the flight square, but then 2.Rxa8+ followed by Kxd3 wins back the minor piece. White won a rook (2 points)
D) 1.d8=N+! is check, and the black king can't go to a square where it will not be forked by 2.Re6+. White wins a Queen for a Rook and a passed pawn. (2 points)
III. Openings
A) 5.e4 (2 points); 5.Bf4 (0.5 points)
B) 5...a6 (2 points); 5...e6 (1 point)
To answer Ecoris' question (Why ...e5 and ...d6 are not candidate moves?) because they're equally good as ...a6, they're just different variations of this opening, thus they're exactly as good. The problem is that I can't give more than one correct answers to choose from. True, I could have chosen your moves, but I choose the Najdorf variation which is ...a6.
C) 4.Nxd4 (2 points); 4.0-0 (1 point)
D) 3.Nf3 (2 points); 3.d4 (0.5 points)
IV. Positional play
A)1.Bc4 to gain tempo on black's queen and develop at the same time (2 points); 1.Bf4 is the second best developing move (0.5 points)
B) 1...e5. If white attacks on the kingside (h5), it's best to counterattack in the centre (2 points); 1...d5 does the same, but is less solid (0.5 points)
C) 1...0-0 is self-explanatory: king safety has key importance in such open positions. (2 points); 1...Bb7 developing is also playable, altough a bit risky (0.5 points)
D) 1...g5. Black wants to eventually 0-0-0, so he can safely advance the kinside pawns, putting pressure on white's future king position (0-0-0 is very unsafe for white due to the fractured pawn structure on that side of the board.) (2 points); 1...Nf5 attacks as well, but white can easily force trade by Bg4 followed by Nh4, where retreating the f5-knight is quite pointless (0.5 points)
V. Endgames
A) 1...Re1+!! saves the game to a draw. White must play Rxe1 (or lose a rook) which is stalemate. (2 points)
B(!!) The most difficult problem in the quiz! So let's see. 1.Ke2? doesn't work. 1...Kh2 and the pawn's path is paved to promotion. Here 2.b5 is too late, best would be 2.Rf1 g2 3.Rf2 (pinning) ...e4 and white loses.
The correct move is the surprising 1.Rf2!!! because it stops ...g2. So ...gxf2 is forced. But now black has no pawns that can be supported by his king, so white can run with his own pawn. The game goes: 2.b5 e4 3.b6 e3 4.b7 f3 but this is not the end of the story! The position is the following:
Now 5.b8=Q?? is a fatal mistake, as it covers h2, leaving the black king with no squares to go, and allowing a stalemate defense strating with 5...e2+ 6.Kxf2 (forced) ...e1=Q+ 7.Kxe1 (forced) ...f2+, 8.Kf1 is stlaemate, other moves allow promotion 8...f1=Q(+) 9.Kxf1 stalemate. So, this is why the problem is rated 4 points. The correct answer for move 5 is b8=R!! where best is ...Kh2 6.Re8 and white wins all the pawns.
C) 1...g3! 2.Nf3+ loses a bishop for black, but also gives him 2 passed pawns, one of them to be promoted. 2...Kg4 3.Nxd4 h2+! Now 4.Kg2 is forced (the alternate Kf1 allows the immediate h1=Q+) ...gxf2 and both pawns can't be stopped (h2 and f2) (3 points)
D) 1.Rxb2 is seemingly a blunder because it falls for a skewer by ...Rh2+. But this is exactly what white is aiming for. 2.Kf3 and white's rook is immune due to stalemate. Any other moves lead to the philidor position (Rook vs Rook+pawn) which is a well-known theoretical draw. (2 points)
+I Bonus questions
A) Again, the mate is only possible if black mates white because of that extra half move. All of black's moves must be a pawn push, otherwise mate is not possible in 5 moves (remember the task is to mate with an underpromotion). The solution runs:
1.d3 e5 2.b3 e4 3.Kd2 exd3 4.Kc3 dxe2. White's moves can be played in different order as well. 5.Kb2 exd1=N# If you can't see things 5 moves in advance, set up a board and play the moves. The final position is:
Note that a3 is covered by black's dark squared bishop on f8.
B) First, if it was white to play, his king would need to block his own bishop, so it would have to stand on b3, but that square is attacked twice. If we put our kijg there, it would be in an impossible double-check. Threrfore it's black to play. But what has white just played?
Not a bishop move, so it must have been a king move. Black cound't have been in check so the white king could't have come from b3. But it is possible that it has captured something. It follows that White's king was in double check from rook and bishop before his last move. We have almost argued ourselves into a corner because this double check appears impossible. The difference is that now there can be another black unit on the board, which is about to be captured by White's king.
The only piece which makes a difference is a black pawn, because it is possible to have stood on c3, as a result of c2-c4 b4xc3e.p.+ followed by white playing Kb3xc3 reaching the pictured position. Therefore the king is on c3.
This problem, as I mentioned, is based on a fact we saw in the previous quiz. It was the "double check without moving either of the checking peces" thing. The answer was the en passant capture, this is what the problem is based on.
Phew, took me awhile to write this all down . Altough this quiz was way more difficult then the previous one, we have excellent results.
I recieved 2 messages, Ihor's and Ecoris'.
First place goes to Ihor this itme with 28.5/46 points
Second place goes to Ecoris, with 24+1/46 points (Congrats to the +1, the bonus questions were difficult even for a master )
Both scores are in the interval of A-class players. Excellent work
____________
|
|
Ecoris
Promising
Supreme Hero
|
|
posted December 14, 2009 01:33 AM |
|
|
Material winning
Quote:
A) White is threatening mate in 3 with his doubled rooks via 1.Rg7+ Kh8 2.Rh7+ Kg8 3.Rag7# but this is defended by the black Queen. So 1.Qb3+! removes it with tempo (check). Black can't take, so Kf8 is forced, then 2.Qxb2 and black is threatened with mate, so he has to move the Rook from f8 to give the king an escape square, so white emerges a Queen ahead. (2 points)
There is something wrong here: Kf8 is not a legal move; f8 is occupied by the black rook.
Quote:
C) 1.Bd3 covers the king's only escape square and also opens up the a-file for white's rook. White threatens mate with two pieces, one of which also threatens a rook, which is immune du to mate. Black can't defend these threats. Best is ...Nxd3 to remove the bishop's attack on the flight square, but then 2.Rxa8+ followed by Kxd3 wins back the minor piece. White won a rook (2 points)
What about 1. ... Rf8 ?
Positional play
C) Is black not concerned about his pawn at b5?
Quote:
D) 1...g5. Black wants to eventually 0-0-0, so he can safely advance the kinside pawns, putting pressure on white's future king position (0-0-0 is very unsafe for white due to the fractured pawn structure on that side of the board.) (2 points); 1...Nf5 attacks as well, but white can easily force trade by Bg4 followed by Nh4, where retreating the f5-knight is quite pointless (0.5 points)
There seems to be a few errors in this puzzle. First of all, g5 is not a candidate move.
Secondly: Is the white bishop supposed to be at h5 instead of h4?
And out of interest, why would black prefer 0-0-0 castling to 0-0?
I don't know how I could miss the solutions involving stalemates in the endgames section. Their solutions were rather straight-forward.
|
|
ihor
Supreme Hero
Accidental Hero
|
|
posted December 14, 2009 09:11 AM |
|
|
Interstingly I also missed those easy stalemates and that enpassant in I+ arghh.
And in V)B) and my move Ke2. I forgot to check Kh2, Rf1 g2, Re1 e4! I almost thought that I got it - I spent a lot of time on this one.
Only 2 participants is terrible  . There were a lot volunteers but we have what we have.
____________
Your advertisement could be
here only for 100$ per day.
|
|
keldorn
Promising
Known Hero
that casts green flames
|
|
posted December 14, 2009 02:59 PM |
|
|
I'm sorry for those errors I made and thanks for Ecoris who pointed them out.
Material winning A): In my explanation, Kf8 is meant to be Kh8.
C): If 1...Rf8, 2.Rxe5 wins a knight. I forgot to add this to the explanation.
Positional C): No, 0-0 is more important here than a pawn. Black makes a positional sacrifice in return for king safety. If he plays ...a6 for instance, white has 2.d5 exd5 3.exd5 and the black knight is forced out of c6, so 4.Qb4 becomes playable, which prevents black from castling (can't castle through check). White thus sets up a powerful attack that can't easily be parried. So, 1...0-0 is the safest.
D): Uhh. I didn't notice that ...g6 should have been ...g5 in the candidate moves. Sorry, full credit for ...Nf5.
Anyway, if black plays ...g5 (or ...g6) then ...0-0 becomes very unsafe. As you can see, white's queenside is wide open, so he plans 0-0. But after ...g5 black's kingside would open up, so he plans to ...0-0-0.
____________
|
|
Ecoris
Promising
Supreme Hero
|
|
posted December 14, 2009 04:09 PM |
|
|
Please take another look at puzzle A) in material winning. As I understand it your solution is:
1. Qb3+ Kh8
2. Qxb2 Rf8
That doesn't match the board displayed. Black is in check again after white's second move, and after after Kh8 white could just win with Rxh8#.
____________
|
|
keldorn
Promising
Known Hero
that casts green flames
|
|
posted December 14, 2009 04:52 PM |
|
|
After deep analysis I found out that this is actually a mate in 5 problem. Initially, when I gave you the puzzle, I analysed only 1.Qb3+ Kh8 2.Qxb2 winning.
Anyway, when you're making a 20-puzzles-long quiz, you don't want to spend time finding the consequences of the solution move. You just know that it's correct, and stop at this point. Next time I'll give myself more time to study what I give you. So, sorry and thanks Ecoris
____________
|
|
Ecoris
Promising
Supreme Hero
|
|
posted December 14, 2009 07:57 PM |
|
|
It was a very good quiz. Small errors will always slip under the radar. But perhaps you should make fewer puzzles. Especially since there are so few who participate.
____________
|
|
keldorn
Promising
Known Hero
that casts green flames
|
|
posted December 14, 2009 08:01 PM |
|
|
Or, we should try doing the same quiz, but in shorter sections.
____________
|
| |
|
|
This thread is pages long: 
