Another Shortest Proof Game

At Chess Publishing Forum, IM John Cox has suggested a new 'shortest proof game' task: What's the shortest game ending with '0-0, mate' or '0-0-0, mate'.

So far the best tries are:
1.d4 e6 2.Qd3 Ke7 3.Bg5+ Kd6 4.Na3! Kd5 5.Qf5+ Kxd4 6.0-0-0, mate


and:

1.f4 f6 2.Nh3 Kf7 3.e3 Kg6 4.f5+ Kxf5 5.Bc4 g6 6.d3 e5 7.0-0, mate.

Both achievements are quite good but I wouldn't be surprised if they can be improved upon.

One would think that short castling must take at least four moves: one knight move, one pawn move to open for the bishop, one bishop move and castling but that isn't necessarily so because Black can capture pieces too.
The same of course goes for long castling.

For those of you still toying with symmetrical mates from my blog entry of April 5th, here are some short games I found:

Knight: 1.e4 e5 2.Nc3 Nc6 3.Nge2 Nge7 4.g3 g6 5.Nd5 Nd4 (Dia)







6.Nf6 mate






Rook: 1.Nf3 Nf6 2.Ng5 Ng4 3.Nxh7 Nxh2 4.Nxf8 Nxf1 5.Ne6 Ne3 (Dia)







6.Rxh8 mate







Bishop: 1.b3 b6 2.Bb2 Bb7 3.f4 f5 4.e3 e6 5.Be2 Be7 6.Bxg7 Bxg2 (Dia)





7.Bh5 mate









Pawn: 1.g4 g5 2.f4 f5 3.gxf5 gxf4 4.Nf3 Nf6 5.Ne5 Ne4 6.f6 f3 (Dia)






7.f7 mate








King: 1.f3 f6 2.Kf2 Kf7 3.Kg3 Kg6 4.Kh3 Kh6 5.e3 e6 6.Bd3 Bd6 7.Bg6 Bg3 8. hxg3 hxg6 (Dia)






9.Kg4 mate.








Any better?

Addendum July 12th
There is a quite readable article on Shortest Proof Games at Chessville. It appears to be the first in a series.

Extreme Symmetry

I will be very busy until the 15th or so but I will try to fill the silence with some mini entries. In my entry of February 22nd I offered two reconstruction tasks:

1) Black's 5th move is to promote a pawn to a bishop with mate.
2) Black's 5th move is to promote a pawn to a knight with mate.

Here are the solutions:
1) 1.c3 d5 2.Qb3 d4 3.Kd1 dxc3 4.Kc2 cxd2 5.Qc3 d1B mate (Dia)

2) 1.d4 e5 2.Kd2 exd4 3.b3 d3 4.Kc3 dxe2 5.Kb2 exd1N mate (Dia)

Today's task can be seen as a prelude to a theme to which I hope to return shortly: Symmetrical positions and the advantage of moving first.

Can you construct a symmetrical game in which White's 4th move is mate?

The usual conditions apply:

All moves must be legal but obviously they don't have to make sense by conventional chess standards.

Unfortunately there are two and a half solutions. There are two different mate positions and one of them can be reached via two slightly different routes.

Good luck!

Two More Retro Challenges

In my entry of July 20, 2007 I offered three games to reconstruct:
1) Black's 4th move is 4...Re1+.
2) White plays the moves 1.f3, 2.Kf2, 3.Kg3, 4.Kh4. Black's 4th move is to give mate.
3) A game opens 1.a3. White's 5th move is to give mate with a rook.

Here are the solutions:
1) 1.e4 h5 2.Qxh5 Rxh5 3.e5 Rxe5+ 4.Kd1 Re1+.
2) 1.f3 e6 (1...e5 will also do) 2.Kf2 Qf6 3.Kg3 Qxf3! 4.Kh4 Be7 mate.
3) 1.a3 e5 2.Nc3 Bxa3! 3.Ne4 (Dia) 3...Bf8! 4.Ra5 Ke7! 5.Rxe5 mate.














For those who enjoy these puzzles I offer two more challenges. For a change I know (or think I know) the originator - American (ex Hungarian) GM Pal Benko - more known for his development of the Benko Gambit than for his endgame studies.

1) Black's 5th move is to promote a pawn to a bishop with mate.
2) Black's 5th move is to promote a pawn to a knight with mate.

The first is relatively simple and I suspect there may be more than one solution. At least I had forgotten the solution, and when I tried to reconstruct it, the solution I found seemed rather unfamiliar. The solution to the second task I find rather surprising and I suspect I would have had problems finding it without the hints I got from an impatient task giver.

More Retro Challenges

Here are a few more reconstruction challenges. How did this happen?













First a simple one. I believe I took less than two minutes to solve it blindfolded (or at least without a board):
1) Black's 4th move is 4...Re1+.

The next one I believe is harder. But I may be mistaken, as it was one of the first I tried to solve:
2) White plays the moves 1.f3, 2.Kf2, 3.Kg3, 4.Kh4. Black's 4th move is to give mate.

The last one probably is the hardest. Some 15 years ago we were three players trying to solve it, one of us a future grandmaster. It turned out that it was the lowest rated - a 1700-player - who showed up in the chess club the next evening with the correct solution:
3) A game opens 1.a3. White's 5th move is to give mate with a rook.

Have Fun!

Retro Games

I suppose everybody with any interest for retrograde games (or shortest proof games) now have had their time to solve the tasks I offered in my March 23 entry:

1) Nunn's ChessBase puzzle 7: Construct a legal game that ends with (the black move) 5...Rh1 mate. Note that the last move is not a capture: 1.g4 h5 2.Bg2 hxg4 3.Bxb7! Rxh2! 4.Nh3! Bxb7 5.0–0 Rh1 mate.

2) Construct a legal game that opens 1.e4 and ends with (the black move) 5...NxR (knight takes rook) mate: 1.e4 Nf6 2.f3 Nxe4 3.Qe2 Ng3 4.Qxe7+! Qxe7+ 5.Kf2 Nxh1 mate.

3) Construct a legal game that ends with this position after EXACTLY four moves (that is eight half moves, four by White and four by Black): 1.e4 e6 2.Bb5 Ke7! 3.Bxd7! (Dia.)

3...c6 4.Be8! Kxe8.

More Retrogames

My first two retrograde game puzzles have already been cracked (see the comments in my entry "Something Entirely Different"), but surprisingly nobody has suggested any solution to the ChessBase nut. That may be because it is considerably harder to solve but also because I didn't really ask for solutions. Be that as it may be, I will repeat the information provided and offer what in my opinion is a related task:

1) Nunn's ChessBase puzzle 7: Construct a legal game that ends with (the black move) 5...Rh1 mate. Note that the last move is not a capture.

2) Related puzzle: Construct a legal game that opens 1.e4 and ends with (the black move) 5...NxR (knight takes rook) mate.

I like to have at least one diagram in my entries whenever natural so here is a nut where the final position is the main key:

3) Construct a legal game that ends with this position after EXACTLY four moves (that is eight half moves, four by White and four by Black).

This kind of short games where you are supposed to reconstruct the entire game by some sparse hints are often called "Shortest proof games". I am not sure that the diagram challenge really belongs in this category, as it is definitely no challenge to reach this position in three moves (six half moves) e.g.: 1.e4 e6 2.Bc4 c6 3.Bxe6 dxe6.

Something Entirely Different

When I in 1977 as a 13-years old boy first visited Kongsvinger Sjakklubb, one of the first sights that met me, was a group of adult players discussing whether it really was possible that this position could occur after only 4 moves:

I happily joined in with my suggestions but after 30 minutes of heavy thinking and discussion and a lot of aimless moving around, we concluded that it was impossible: The two knights simply could not both capture each other and it was not time for other pieces to capture them and return to its original squares.

Well, it turned out that it was possible after all, but only after the person who had offered the puzzle (standing sniggering in the background all the time) demonstrated the solution. Since that day I have had a fascination for this kind of retrograde puzzles, and collected whatever I have come across. Unfortunately the composer (originator/creator?) of the puzzle very rarely is provided.


Sometime around 2000, I was offered this seemingly related puzzle:

Can this position occur after only 5 moves? Surprisingly knowing the solution to the previous puzzle does not make it easier at all.

Judging from the reactions to puzzle No 7 at the
ChessBase Christmas Quiz, I am not the only chess-player fascinated by this kind of useless brain exercizes. You can safely look at the readers' feedback - all spoilers have been removed.

I will return with solutions (also for the ChessBase nut, which is quite hard) in a few days.

Frustrated Note:
It seems that I cannot add a link to the ChessBase Christmas Quiz. I have no idea why, but here it is as a text string: http://www.chessbase.com/puzzle/christmas2006/chr06-9a.htm.

WARNING!
If you want to solve the puzzles yourself, be careful. I will allow spoilers in the Comments below (they will become visible if you open a post by clicking the header or if you click the "Comments" link below).