# No.1299 (AO)

 No.1299 Алексей Оганесян (Россия) Оригинальные Retro & PG задачи JF – R2017-18

 No.1299 Aleksey Oganesjan Russia original – 22.05.2018 Solutions: (click to show/hide) white Ke1 Rh1 Bd3e5 Pd2f6h5h7 black Kh6 Bg8 Pf7g4g5 #1     b) Ke1→f5 ; c) Kh6→f3    (8+5) a) 1.h7*g8=S # ! {(1.h8Q/R#? Bh7!) 1.hxg6 e.p.#?? - не факт, что последним ходом черных был 0...g7-g5.} b) wKe1-->f5 1.h5*g6 ep.# ! {(1.hxg8S#? Kh7!) Без сомнений, последним ходом черных был 0...g7-g5, но не 0...Kg7-h6, т. к. в этом случае белая пешка не смогла бы попасть на f6.} c) bKh6-->f3 1.0-0 # ! {(1.Rf1#? Kg2!) (C+ by Popeye 4.79)} #1 с чистым белым Валладао в довольно экономичной позиции – всего 13 фигур с неплохой их загрузкой. Сравните с pdb/P0000424 – также #1 с белым Валладао, но с «поворотными» близнецами и тяжелой 20-фигурной конструкцией со многими слабо загруженными фигурами. (Author)

### 23 комментария: No.1299 (AO)

1. Ladislav Packa пишет:

Something is wrong, maybe wPe2 should be on d2.
This is a type of problem that can be labeled as “lost”. They are not orthodox, and there is too little retro. I know this from my own practice, publishers have the problem to find the right column for them …

• Aleksey Oganesjan пишет:

Yes, you are right – wPe2 should be on d2.

• Julia пишет:

Corrected Pe2 -> d2.

2. Dmitri Turevski пишет:

Are the “rotational” twins (as intended in P0000424) really inferior compared to the twins where thematic pieces (here – both kings) are displaced?

• Aleksey Oganesjan пишет:

In general – no, “rotational” twins are not inferior, of course. But concretely in P0000424, its heavy construction with many little-used units makes a bad impression, to my taste…

• Dmitri Turevski пишет:

In P0000424 the only missing white piece is wBf1.
This means that
1) Last moves could not be dxe3/dxe5
2) wBb8 is not promoted, and the check was given by the battery Rd6-f6+, which, in turn, leaves out the possibility of e6-e5, so the only possible last move is e7-e5.

I could be wrong, please correct me if so, but this concept seems to naturally require 15 white men on board.

3. Aleksey Oganesjan пишет:

>> this concept seems to naturally require 15 white men on board.

I think so: if one or several officers/pawns was set only for “retro-legality” of position and not for active participance in the play or in the mate, – then it is not very good.
In P0000424 some white pawns are not need at all for the play and need only for that a quantity of white units equals 15 (for “retro-legality” – for impossibility of 0…dxe3/dxe5).

>> In P0000424 the only missing white piece is wBf1.

I means the following:

P0000424 – 6 white pieces:
a) 3/6 pieces are need for the play (and Qg8, Sh7, Rh1 are NOT need. I count Rf6 as necessary for the play because it provides e.p.);
b) 3/6 pieces are need for the play (and Qg8, Rf6, Bb8 are NOT need);
c) 2/6 pieces are need for the play (Rf6, Rh1, Sh7, Bb8 are NOT need).
3/6 + 3/6 + 2/6 = 1,33 instead ideal 3 (44 %)

My problem – 3 white pieces:
a) 2/3 pieces are need for the mate (and Be5 is NOT need);
b) 2/3 pieces are need for the mate (and Bd3 is NOT need. I count Be5 as necessary for the play because it provides e.p.);
c) 3/3 pieces are need for the mate.
2/3 + 2/3 + 3/3 = 2,33 instead ideal 3 (78 %)

And we see: total loading of white pieces is equal 44 and 78 % respectively.
It was a minute of math in this site :))

4. Vlaicu Crisan пишет:

Interesting to compare with another Valladao composition from more than 20 years ago with the stipulation ‘Last move?’ – see P0006515.

• seetharaman пишет:

The Juraj Lorinc Problem is remarkable. I give the diagram only if anyone likes to solve.

Stipulation: Last move?
(b) Patrol Chess (c) Isardam

• seetharaman пишет:

The white knight seems to be needed for only part c.

• Juraj Lörinc пишет:

There are more pieces that are needed in mechanism only in one phase, but then the difficult part was to put everything together so that there are no other last moves possible. I mistily remember having many positions with many more pieces, cooks etc. At the end I was quite satisfied with outcome, as non-retro composer.

Thanks to all for praise, I am glad you liked the problem.

• Geoff Foster пишет:

Why is the white knight needed in part (c)?

• Geoff Foster пишет:

Oh now I see, in (c) the white knight prevents Sb2xBd1 and Sf2xBd1.

5. Ganapathi пишет:

Seetha,
diag. Last move 1.d4:e3 ep after Whites e2-e4
b)) 1.0-0
But what is the move in c)?

• Ladislav Packa пишет:

c) 1…c2:Bd1=S

6. Ganapathi пишет:

• seetharaman пишет:

In Isardam only way for black to check with Ba8 is to capture a white bishop on d1 (because white’s other possible last move e2-e4 illegal)
So the last move was c2:Bd1=S.

7. Geoff Foster пишет:

Clever! In all parts the wK is in an apparently illegal check. (a) uses the en passant trick, in (b) the bBa8 has become observed by bRf8 through castling, while in (c) a wBd1 would prevent Bxf3 because of Isardam.

8. Geoff Foster пишет:

Is the bPf5 needed so that in (c) Pe2-e4 is illegal? According to Popeye the move Pe2-e4 is illegal anyway, because the wPe4 is observed “en passant” by the bPd4. That is, there is no need for the observation to be mutual.

• seetharaman пишет:

For Isardam the move is illegal if “a Madrasi type paralysis will result.” Here does any paralysis occur? 🙂

• Juraj Lörinc пишет:

But Pf5 is also needed to avoid Be4-a8+ in b).

• seetharaman пишет:

I too failed to notice it! I agree with Geoff Foster, the problem has many subtle points!

9. Geoff Foster пишет:

This problem is more subtle than I realised!