MatPlus.Net

 Website founded by
Milan Velimirović
in 2006

19:06 UTC
ISC 2021
 
  Forum*
 
 
 

Username:

Password:

Remember me

 
Forgot your
password?
Click here!
SIGN IN
to create your account if you don't already have one.
CHESS
SOLVING

Tournaments
Rating lists
1-Oct-2021

B P C F





 
 
MatPlus.Net Forum Selfmates Logical problem with false plan
 
You can only view this page!
(1) Posted by Aleksey Oganesjan [Monday, Oct 4, 2021 14:01]

Logical problem with false plan


New (??) opportunity to expand a content of logical problems:

1) there is a try 1.Х? - false main plan that is not succeed due to some obstackle;
2) there is another try that begins with false foreplan 1.Y?, after which the false main plan X is threatening. But the plan X is not succeed again, herewith of course for some other reason (for example, during execution of false foreplan, White allow a new weakness that Black uses);
3) of course there is no successful realization of the false main plan (that's why it is false!);
4) further - everything is as in an usual logical problem: an actual main plan, its unsuccessful attempt at the beginning and successful after an actual foreplan.

It seems that a major difficulty is to achieve that the false plan is somehow clearly connected with the actual solution. Otherwise, a couple of false tries of the false plan can be seemed artificially "screwed" onto the rest of the solution.

Aleksey Oganesjan
Belyakin-100 MT, 2021
I-II Prize
(= 10+12 )

s#9

False main plan: 1.Qb8+? Rxb8 2.axb8B – 3.Be5 – 4.Rxg8+ Bxg8#, but 2...Sxb5! 3.Be5 Sd4+! 4.Bxd4 cxd4!
False foreplan: 1.Rxa3? (2.Qxb8+ and etc.), but 1...b1B! 2.Qb8+ Rxb8 3.axb8B Bf5+! 4.Ke5 – Black responded symmetrically to the threat of promotion in Bishop, and White did not have time to block e5.

Actual main plan 1.Qe5? is not succeed at once because in a few moves White Queen will need access to c5, which is now guarded by Black Bishop. Therefore, White needs to interfere this Bishop first.
Actual foreplan:

1.e4!

It's threatening 2.e5 ~ 3.Rxg8+ Bxg8#, and any attempt to check to wK leads to checkmate: 1...Sxb5 2.e5 Sxc7(d4)# or 1...b1Q(B) 2.e5 Q(B)f5#.
That's why Black is forced to en-passant capture:

1...fxe3 e.p.

And now – a familiar plot: forcing of castling and further uncastling for elimination of obstackle of main plan.

2.Qe5! 0-0-0 3.Bb7+ Kxb7 4.a8Q+! Rxa8 5.Rxb6+ Kc8 6.Qxc5+ (that's why White needed to interfere Bf2!) 6...Kd8 7.Qc7+ Ke8 8.Qe5! ~ 9.Rxg8+ Bxg8#.

Concept of problem: in false plan White eliminates Black castling by "ordinary" way but fails; in actual plan White uses non-standard way for eliminating of castling (well-known by https://yacpdb.org/#424634) – by forcing of it and further uncastling.

As compared with the pointed out partial self-anticipation, there were added: false plans, actual foreplan 1.e4 fxe3 e.p. and thus Valladao, a removal of dual a8Q(B)+.
 
(Read Only)pid=21633
(2) Posted by Mark Kirtley [Wednesday, Oct 13, 2021 23:26]

Aleksey, thanks for showing this cool problem. I also tried 1.Bxh8 for another "ordinary" way of eliminating Black's castling option, while supporting the actual main plan, and I see why it doesn't work.
I myself have tried to compose a logical selfmate with foreplan, but I've yet to be successful!

It seems to me that your recent selfmate in The Problemist might trick many a solver into thinking it is logical problem with foreplan. I'll quote the problem here, now that the solution has been published, and then say what I mean.

Aleksey Oganesjan
S2849, The Problemist, March 2021
(= 11+8 )

S#8

solution: 1.Rc2+ Sc4 (1...Sxc2? 2.b4+ Scxb4#) 2.Qf2+ Sde3 3.Rf5+ Bd5 4.Sxd5+ Qxf8 5.Sxe3+ Qxf5 6.Sxc4+ Qxf2 7.Sxb6+ Qxc2 8.Sa4+ Qxa4#.

(What a problem!) Now what I mean is, 1.b4+ Sxb4# would work as an actual main plan, if some way could be devised to get the wQ off the 5th rank, and that way would be the actual foreplan. But there is no such way! So I wonder if it is fair to say that viewing the problem as logical is a sort of try!
 
 
(Read Only)pid=21648
(3) Posted by Aleksey Oganesjan [Thursday, Oct 14, 2021 08:45]

Dear Mark, thank you!

Hm, yes, in my s#8 the move 1.b4+? Sxb4#?? can be consider as a "false main plan". By the way, it's can be compared with my s#10 (https://pdb.dieschwalbe.de/P1359754) where a main plan (real, actual!) 1.e4+ fxe3ep# is also initially unlucky in view of pin, but in that s#10 the White finds a way to unpinning, unlike s#8!
 
   
(Read Only)pid=21649
(4) Posted by Joost de Heer [Thursday, Oct 14, 2021 12:57]

 QUOTE 

By the way, it's can be compared with my s#10 (https://pdb.dieschwalbe.de/P1359754) where a main plan (real, actual!) 1.e4+ fxe3ep# is also initially unlucky in view of pin

Main plan fails because the mating piece can be captured, not because it's pinned.
 
 
(Read Only)pid=21650

No more posts


MatPlus.Net Forum Selfmates Logical problem with false plan