8/K3k2p/P7/8/8/8/r7/5R2 w – – 0 1
White to move. What is the best continuation for White?
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1.Rb1
If 1…Kd7
2.Kb7
1…Kf6 is a better practical try. And then?
After 1. Rb1 Kf6, white can move 2. Kb2 to make way for pawn promotion.
1. Rb1 Kf6
2. Rb8 Rd2
3. Ka8 Ke7 maybe
4. a7 h5
5. Ra6 h4
6. Kb7 Rd7+
7. Ka6 and the pawn will queen
“After 1. Rb1 Kf6, white can move 2. Kb2 to make way for pawn promotion.”
2…Kf5
“1. Rb1 Kf6
2. Rb8 Rd2″
Not sure I understand the idea behind 2.Rb8?! 2…Kg5 followed by …h5 draws easily.
I am looking at the tablebase, and am therefore hors concours
There should still be rewards for having the rigor to consult the tablebases, relay the finding and then learn by asking ‘why’? If it’s good enough for John Nunn, it should be good enough for us.
So, http://www.k4it.de/ says:
1. Rb1!! Kf6 (Ke6 allows 2 winning moves)
2. Rb5!! (other moves draw)
Wondering what db bb looks at 🙂
Aim to get R behind P
K can guard R moving Ra5
2…Re2 (toa, the tougher optimal-ask)
3. Kb6! (Ka8,Kb7,Kb8 also win)
3…Re6+ (‘toa’ again)
4.Ka5! (R-shielding K instead)
4…Re1 (toa, win clear now?)
5.a7! (but many win-retainers)
Did no one found 2. Rb5! without table bases?
It is an old known fact (or thing of counting) that in a game K(distant)R vs KP the pawnside king shouldn’t be allowed to reach the forth (fifth if black) row.
In this case it means that if we took away black rook and white pawn and white rook on the fifth rank and black’s king goes to g6 (to defend h5 not to allow Rb5-h5 after which white won easily) and runs with his pawn afterwards white can play (as soon as the pawn is on h3) Rb5-b3! h2 (forced; see: if the black king was just one rank closer to the first rank here a king move would defend the pawn and the game was draw) Rb3-h3 1:0
With the black king on the fifth rank white’s rook must be sacced against that pawn after black sacced his own rook.
So the only maneuver can be 1. Rb1 2. Rb5! and rest is a thing of counting – counting if it’s a draw or a win for white.
And it seems as if white was winning.
1. Rb1, Kf6 2. Rb5, Kg6 3. Kb7, h5 4.a7, h4 5. a8Q, RxQ 6. KxR and we are in the winning position above.
Other probably better try in a practical game:
1. Rb1, Kd6! 2. Rb5?, Kc7 (=)
so 2. Kb7 is forced. 2. -, Ke5! white’s threat was 3. Rb5! again, so Ke5 is the only chance black has.
I think now white has to find the correct idea which isn’t easy to find in a practical game.
Enticing away the black king as far as possible. Winning the black pawn with the white rook. Return to the queenside and free the king and queen the pawn.
Again it is a good thing of counting how to play to
1) distance the black king from the important square c7
2) not allow the black king to get a poition where he can
a) defend the pawn
b) is closer to the first rank than the fifth rank.
Black’s threat after 2. -, Ke5 is 3. -, Kf5! with the threat of Kg4 and h5 or if Rh1 than Kg6 followed by h5 and Kg5 (or Kf5 if Rg1+) and it’s draw like seen above.
[Not 3. -, Kf4? 4. Rh1!, Ke5 (what else?) 5. Rxh7, Kd6 6. Kb7, Rb2+ 7. Ka8 (threat of 8. a7 and 9. Rb7) 1:0]
So after 1. Rb1, Kd6! 2. Kb7, Re5 3. Rb5+! seems to be the only winning move.
3. -, Kg6 leads to a known position and 3. -, Kf4 4. Rh5! does so, too.
Summary:
1. Rb1, Kf6 2. Rb5 isn’t hard to find because it is the only chance for white to win this.
1. Rb1, Kd6!? gives black much more practical chances to draw but 2. Kb7, Ke5!? 3. Rb5+! (such a check is very hard to find in a game!) seems to win for white though.
Regards
Jochen
PS: I did not use any engine or table bases, why should I?
Perhaps there are mistakes in my analysis (I did not use a board this time so the mistakes may be big) but using machine help for Susan’s puzzles doesn’t make any sense….
Go easy on me, Jochen: I was at the office! 🙂
“So after 1. Rb1, Kd6! 2. Kb7, [K]e5 3. Rb5+! seems to be the only winning move.”
3.a7 works, too, but I agree that 3.Rb5+! is more elegant.
One can learn a lot about Rook endings by noodling around with variations in this very instructive position.
Rb1 wins in 29 moves and is the only winning move.
Basic 6 piece table base should pop this out ASAP.
All other 1st rank Rook moves draw – except the losing Ra1.
All Rook lifts, except the losing Rf2, up to f5 draw.
The interesting thing is K to b6, b7 AND b8 also draw!!
So 1 win and 11 draws are possible.
Knowing shelter ideas, Rule of 5 and Vancura’s Position are key to finding winning and drawing patterns.
Peter / chesstoplay