## Friday, December 30, 2011

### The twelve puzzles of Xmas

[This study is cooked! Scroll down for replacement puzzle]

Troitzky, 1906

White to play and draw

Replacement puzzle below!

Bruski, 1906

White to play and mate in three

Anonymous said...

I don't understand this one.
Why don't all of 1.Bb4, 1.Kb7, 1.Kd7 and 1.Kd5 draw?

ejh said...

Why would you think they do?

Anonymous said...

Because after 1.Kb7/d7/d5 B somewhere on the long diagonal eg f4 2.Ba3 Kxa3 3.e7 c1=Q 4.e8=Q is drawn.

I am guessing that the intended point is that 1.Bb4 Bf4 2.Bd2 Bxd2 3.e7 c1=Q+ 4.Kd7 draws since Black can't prevent White queening, whereas 1.Bc5? Bg5 2.e7 (2.Be3 Bxe3 3.e7 c1=Q+ 4.Kd7 Qd1+ wins) 2....Bxe7 3.Be3 Kb1 4.Kd5 Ba3 wins e.g.: 5.Kc4 Bc1 6.Bc5 Bh6 7.Ba3 Bg7 8.Kb3 Bf6

So what have I missed?

ejh said...

You may be right! I was looking at 2...Bg5 but 3.Bc1! seems to draw in that instance, don't you think?

Thanks very much: I'd be interested in the thoughts of other readers as to whether the study is cooked. In the meantime, if you give me a few minutes I'll see if I can put up something else from 1906....

ejh said...

...which is now up. Apologies for any inconvenience. Of course I assume the replacement will also be flawed...

Anonymous said...

Tablebases confirm Troitsky (with s or z) is cooked with Anon1's four starting moves all drawing. 1. Kb5 meets a nasty end: 1. ... Be3 2. Ba3 Kxa3 3. e7 c1=Q 4. e8=Q Qc5+ 5. Ka6 Qb6#.

The replacement appears to have a rather elegant solution. In the starting position, Black has five legal moves: White increases that to six with the key.

Richard James said...

The tablebases confirm that all four of Anon's moves draw. I entered the position at http://www.shredderchess.com/online-chess/online-databases/endgame-database.html. What was your source, Justin?

ejh said...

My source was Abrahams, Not Only Chess, Allen and Unwin, 1974. Pre-computer, obviously. I suppose it should have occurred to me that Nalimov would have been able to check this one. (My rather weird program can't actually solve anything, not even a mate in two.) New technology baffles sober old hack.

Campion said...

The replacement problem's been bugging me on and off throughout New Year's Eve, even with Anon's hint. Have finally cracked it (after trying all the queen moves and staring wistfully at h8, finally looked at the most "outrageous" move). Even then it was only desperation that led me to find the only way round Black's 1...Nc4 defence.

Lordy, that was annoying.

Have to say that contrary to Anon's opinion, the solution struck me less as elegant and more as "taking the piss". But that could well be just sour grapes.

ejh said...

Well, there's a nice line after 1...Nc4. But anyway, the solution is....

Anonymous said...

I was lucky enough to spot 1. ... Nc4 2. Qxb3+ Kxb3 3. Rd3# pretty quickly, presenting the key 1. Rd6! on a plate.

The threat is 2. Rd2 ~ 3. Ra2# and the only other defence is 1. ... exd6 2. Qh8 ~ 3. Qa1# (except 2. ... b2 3. Qxb2#).

ejh said...

And that's so. From Akademische Monatshefte für Schach, 1906. I found it in Pandolfini, Think of the Whole, The Q&A Way 114, on the Chess Café website.

ejh said...

I should have added that according to Abrahams (p.186) the cooked Troitzky study was from Deutsche Schachzeitung, 1906.