34 Rc4

Option 1) for black
34... bxc4, 35 Bc5 Rc1, 36 b3 Kf1, 37 Bxf2 Kxf2, 38 b2 Rxc2, 39 b1=Q winning

Option 2) for black any other move that moves the rook on f2 or king

35 Rc3 attacking pawns on b3 and g3 and protects the valuable pawn on c2

Option 3) for black any other move that moves does not move the rook on f2

35 Bc5 pinning the rook on f2

but I found out it does not work since 34..Bc5 35.Rxc2 Rc4 36.Rcf2

only 34..Rc4! wins right away. What a shock it must have been to opponent.

A) 35.bxc4 Bc5

A.1) 36.Rc1 Bxf2+ 37.Kxf2 b3 38.c5 b2 39.c6 b2xc1=Q 40.c7 Qd2+ 41.Kf3 c1=Q - +.

A.2) 36.Kg2 Bxf2 37.Kxf2 (37.Rxf2 c1=Q) b3 38.c5 b2 39.c6 c1=Q - +.

B) 35.Rc1 Bc5

B.1) 36.bxc4 transposes to A.1.

B.2) 36.Rcxc2 Rxc2 - +.

B.3) 36.Kf1 Bxf2 37.Kxf2 (37.bxc4 b3) Rc3 (now, the immediate 38... Rxb3 39.Rxc2 Ra3 is questionable because of 40.Rc8+ Kf7 41.Rc7+ and 42.Rxa7)

B.3.a) 38.Ke1(2) (the king attacks the pawn on c2) a5 39.Kd2 Rxg3 40.Rxc2 (40.Kxc2 Rc3+ winning the pawn endgame) Rg2+, etc.

B.3.b) 38.Kg2 (the king defends g3 passively) a5 39.Kf2 Kf7 40.Kg2 Ke7 41.Kf2 Kd7 42.Kg2 Rxb3 43.Rxc2 Ra3 44.Rd2+ Ke7 45.Rc2 Rxa4 46.Rc7+ Kf8 47.Rc8+ Kf7 48.Rc7+ Kg6 49.Re7 b3 50.Rxe6+ Kf7 51.Rb6 Rb4 - +.

B.3.c) 38.a5 (trying to fix Black's a pawn) a6 39.Kg2 Rxb3 40.Rxc2 Ra3 41.Rc8+ Kf7 42.Rc7+ Kg6 43.Re7 Rxa5 44.Rxe6+ Kf7 45.Rb6 Ra2+ 46.Ke3 a5 and Black should win.

B.3.d) 38.h5 h6 and Black will trade his g pawn for White's h pawn, improving the position of his king and reverting to the previous lines.

Usually I dedicate at most 2 minutes to the problem and call it a day and look at the solution... but something about today's problem made me go on looking... and gradually the idea came:

first, that the b4 pawn is also a participant... then, that taking a c4 rook by means of bc isn't necessarily winning for white... then the idea about a 6th+7th rank pawn couple being stronger than a rook... then I sat down and worked the move order - and I had it solved.

I think you're right (I should have been more careful), probably is better 35.Rxc2 Rc4+ 36.Rcf2 Bxf2+ 37.Kxf2 Rc3 38.Rd1 activating the rook and creating counterplay: 38... Rxb3 (38... a5 39.Rd8+ Kf7 40.Ra8) 39.Rd1+ Kf7 40.Rd7+ and 41.Rxa7.>

<34....?>

Target: 3:30;000
Taken: 2:27;700
Par: yes

Material: /+ / ds&\

Candidates: Rd1, c1=Q, <[Rc4]>

-ML-
Woah, this move is shocking. Black seems to gain the upper hand due to a possible pin on the Rook on f2. The Black Rook is in the way, and this Rook and do two simultaneous tasks by going to:

<34....Rc4!!> a mere mortal might not even consider such a move OTB. Now, with the puzzle tag, this becomes only a tad bit more obvious. White can NOT capture this Rook, albeit being two Rook vs Bishop up afterwards!

/A\
<35.bxc4 Bc5 36.Kg2 (36.Rc1 b3 with Bxf2 and b2) Bxf2 37.Kxf2 b3 > and the pawns, created due to the capture on c4, cannot be stopped by the Rook. So from two Rooks vs Bishop down, Black creates a full Queen up.

/B\
<35.Rc1> now only this remains as a logical move to stop the c-pawn.

<35....Bc5!> of course! 36.bxc4 is still losing due to the now, even simpler, 36....Bxf2† 37.Kxf2 b3 .

<36.Kg2> what else? Now White IS threatening bxc4.

<36....Bxf2 37.Kxf2 Rc3> and the weak pawns are breaking White up.

<38.Ke2 Kf7 39.Kd2 Rxg3 40.Rxc2 (40.Kxc2 Rc3† ) 40....Rg2† 41.Kc1 Rxc2† 42.Kxc2 h6 43.Kd3 g5 44.hxg5 hxg5 45.fxg5 Kg6 46.Kc4 a5 > and White has no option to counterattack due to the passed f-pawn.