Monday, June 3, 2013

Another look at Aron-Jianwen ending

After Sumant commented that the ending is drawn, I decided to analyze it in more detail. I start with this position as black cannot prevent white from achieving it.


The next step for white is to cut off the black king from the f5 pawn. Black cannot stop this but he can decide whether he is cut off on the rank or on the file. The game continued

1...Kf4 2. Rb8 Ke4 3. Rf8 Bb2 4. Kg5





Now black made a fatal mistake with 4...Bc3  ?? and lost after 5. Rf7?  Bb2?? 6. Kg4 Bf6 7. Ra7 Ke5 8. Ra6 Kd5 9. Re6 . The black king is cut off along the e-file and white won as in the actual game.

From the diagram above, black had only one drawing move, 4...Kf3! White cannot
improve his position for example, 5. Rb8 Bf6+ 6. Kg6 Kf4 7. Rb4+ Kf3 ! (Not 7...Ke5 8. Rb6 and black is in zugzwang). Black is cut off on the 4th rank but this is alright as white cannot maintain this and attack the g7 pawn e.g  8. Kh5 Kg3! 9. Kg6 Kf3 10. Rb7 Kg4 (Whenever the rook attacks the g7 pawn, black just ensures that his king is around f4 or g4) 11. Rd7 Kf4 draws


4 comments:

Anonymous said...

I think that even after my king is cut off on the e file, it should still be a draw( other players told me this too). I must play be5 and get my king back across to attack the f pawn and I should be OK. But this method is more risk free. Thanks for the analysis mr.Jimmy :)

Jianwen

Jimmy Liew said...

With your king cut off on the e-file, you will lose the g-pawn or your king will be driven further and further away and eventually lose.

Main Simul said...

From move 66.Rxc3+ until move 92.Rxg7,
there are 53 positions created
with 6 pieces or less on the board.
We can use the Nalimov EGTB (End Game Table Bases)
at http://chessok.com/?page_id=361
to check the position endgame results.
Nalimov EGTB calculation says 34 positions are Draw
and 19 positions are Mate in XX moves as listed below:
1) 66.Kg4 : FEN 8/6p1/8/3K1Pb1/6k1/2R5/8/8 w - - 0 67 : Mate in 28 moves
2) 81.... Ke4 : FEN 1R6/6p1/5bK1/5P2/4k3/8/8/8 w - - 0 82 : Mate in 76 moves
3) 83.... Bc3 : FEN 5R2/6p1/8/5PK1/4k3/2b5/8/8 w - - 0 84 : Mate in 73 moves
4) 84.... Bb2 : FEN 8/5Rp1/8/5PK1/4k3/8/1b6/8 w - - 0 85 : Mate in 73 moves
5) 85.Kg4 : FEN 8/5Rp1/8/5P2/4k1K1/8/1b6/8 b - - 0 85 : Mate in 72 moves
6) 85.... Bf6 : FEN 8/5Rp1/5b2/5P2/4k1K1/8/8/8 w - - 0 86 : Mate in 72 moves
7) 86.Ra7 : FEN 8/R5p1/5b2/5P2/4k1K1/8/8/8 b - - 0 86 : Mate in 71 moves
8) 86.... Ke5 : FEN 8/R5p1/5b2/4kP2/6K1/8/8/8 w - - 0 87 : Mate in 70 moves
9) 87.Ra6 : FEN 8/6p1/R4b2/4kP2/6K1/8/8/8 b - - 0 87 : Mate in 69 moves
10) 87.... Kd5 : FEN 8/6p1/R4b2/3k1P2/6K1/8/8/8 w - - 0 88 : Mate in 67 moves
11) 88.Re6 : FEN 8/6p1/4Rb2/3k1P2/6K1/8/8/8 b - - 0 88 : Mate in 70 moves
12) 88.... Bd8 : FEN 3b4/6p1/4R3/3k1P2/6K1/8/8/8 w - - 0 89 : Mate in 67 moves
13) 89.Kh5 : FEN 3b4/6p1/4R3/3k1P1K/8/8/8/8 b - - 0 89 : Mate in 71 moves
14) 89.... Ba5 : FEN 8/6p1/4R3/b2k1P1K/8/8/8/8 w - - 0 90 : Mate in 21 moves
15) 90.Kg6 : FEN 8/6p1/4R1K1/b2k1P2/8/8/8/8 b - - 0 90 : Mate in 20 moves
16) 90.... Bc3 : FEN 8/6p1/4R1K1/3k1P2/8/2b5/8/8 w - - 0 91 : Mate in 20 moves
17) 91.Re7 : FEN 8/4R1p1/6K1/3k1P2/8/2b5/8/8 b - - 0 91 : Mate in 19 moves
18) 91.... Bb2 : FEN 8/4R1p1/6K1/3k1P2/8/8/1b6/8 w - - 0 92 : Mate in 19 moves
19) 92.Rxg7 : FEN 8/6R1/6K1/3k1P2/8/8/1b6/8 b - - 0 92 : Mate in 18 moves
For reference,
Recorded Game of National Closed Championship 2013
Round 8 Board 1 on Friday 31/May/2013 at 3:00PM:
Aron Teh Eu Wen (1949) vs. Wong Jianwen (2084) 1-0
http://chess.tuxtown.net/game-replayer.php?id=51a88b43adbacc195e600a91c8d654d070a30fc74400704ae448d

Indera Shahrin Mokhtar said...

I use this link to analyse this position:http://www.shredderchess.com/online-chess/online-databases/endgame-database.html. It is drawn position. Black choose the best continuation 4...Kf3 which secure drawn.

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