Endgame analysis : white to play and..?

Question

R3nk21B1K4/4r3/4P3/3Pb3/8/3P4/8/1B1K4 w - - 0 1

White to play and ?, D.Antonini 09/2017

I wouldn't qualify this position as a study, at least according to modern canons for study composition, as there are a few duals (interversion ones) and a few other defaults. I prefer to present it as a practical endgame position worth having a look at.

Therefore I won't even give a specific statement : white to play, and it's up to you to figure out if they can win or only draw. I must warn you it's rather difficult to analyse this position accurately. There is one concealed idea (and programs won't be able to help much figuring it out). But I'm sure you'll feel pretty happy once you manage to figure it all out - if you do (but with brillant chess composers like Noam Elkies around, I'm sure some of you will manage to).

Answer 1

First thoughts:

We are obviously looking for a win for White. Making a draw is no challenge, you just have to exchange either the rook or your bishop even if you lose all three pawns in the process. 1.d4, 2.Bg6, 3.Bxe8 is a straitforward draw.

If we do nothing dramatic, Black can blockade with ...Kg7 and ...Bd6, when he cannot be worse. So let's go for direct play trying to exploit the pin on the 8th rank:

1.d4 Bd6 (or 1...Bd4 when 2.Bg6 might be the best try but the hand wants to play 2.d6 Rxe6 3.d7 Bf6 (or Bb6) and Black seems to draw thanks to ...Kg7 or ...Rd6+ - looks like a good line in which one can look for pretty ideas...)

2.Bg6 Kg7 (Black can also wait with his bishop, but White will try to bring in his king and maybe create a zugzwang of some sort)

3.Bxe8 (3.Rxe8 Rxe8 4.Bxe8 Kf8 is a dead draw) and with the rooks on the board White may well be able to break the blockade.

Well, there is probably a win hiding somewhere in those lines, but it is not an easy one.

Answer 2

I just remembered I totally forgot to come here post the solution. My apologies but better late than never :).

The main interest of this position is the apparent mutual zugzwang soon appearing after 1.d4 Bd6 2.Bg6, when playing natural moves and bringing the white king to f5 (in the position white : Kf5, Ra8, Bg6 pawns d4,d5,e6/ black : Kf8,Re7,Bg3,Ne8).

In that position If black is to play (which is the case ine the soçlution below after 13.Ra8), black loses very quickly (1...Bh2 loses the possilibility to play bh4+, so 2.Bxe8 Rxe8 3.Ra7 (threatening 4.Rf7+ followed by 5.Rd7 and the d pawn will be able to move to d6)3...Rb8 4.Kf6 (and bh4+ not possible anymore with the B on h2).

On the other hand, with white to play (which would be the case in the solution below if white would chose to play the natural 6.Kf5), it's much harder to figure out how to win. The triangulation manoeuver requires to bring the white king to g4 and the white bishop to h5 (which aren't very naturlal ideas), before trinagulation with the rook (although the move order doesn t matter, you can olay 1.Rc8 Fh2 first, then bring the king to g4 and then the bishop to h5, or play Kg4 first or Bh5 first), but the traingulation manouever itself stays unique and the only way to win (just interversion duals).

I'll just put the solution as is, I'll try to go into more details if some things aren't clear :

1.d4 Bd6 (i)
2.Bg6 Bb4
3.Ke2 Bd6
4.Kf3 Bc7
5.Kg4 Bh2! (ii)
6.Bh5 Bc7! (iii)
7.Rc8 Bh2! (iv)
8.Rd8 Bc7
9.Ra8 Bh2! (v)
10.Rc8 Bd6
11.Bg6 Bh2
12.Kf5 Bg3
13.Ra8 Bh2
14.Bxe8 Rxe8
15.Ra7 Rb8
16.Kf6 Rb1
17.Ra8+ Bb8
18.d6 +-

(i)1....Bxd4 2.d6! Rxe6 3.d7! Bb6 4.Bf5! Re7 5.Bg4! +-
(ii)5...Bd6 6.Rc8 Bh2 7.Kf5 Bg3 8.Ra8 +-
(iii)6...Bd6 7.Kf5 Bg3 8.Bg6 +-
(iv)7...Bd6 8.Bg6 Bh2 9.Kf5 Bg3 10.Ra8 +-
(v)9...Bd6 10.Kf5 Bg3 11.Bg6 +-