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Up Topic The Rybka Lounge / Test Positions / 5 hard positions
- - By dorszcz (*) Date 2018-11-20 22:03
r3k2r/bppbqp2/P1np2n1/1B6/3pP1p1/P1P3B1/3N1PPN/R2Q1RK1 b kq - 0 19

3r3r/k7/2p5/1pPp1p1p/pP2pPpP/P1K1P1P1/2b5/BN6 w - - 0 1

8/2pb1k1K/3p2p1/5pP1/2PPpB2/PP6/8/8 b - - 0 1

8/8/N1p1P1p1/3p3p/8/b1kP4/P7/7K w - - 0 1

r1qn1rk1/p1pp1ppp/1p2p2b/1P2P3/P7/R2B1N2/1P4PP/3Q1R1K w - - 0 17
Parent - - By user923005 (****) [us] Date 2018-11-21 00:45
8/8/N1p1P1p1/3p3p/8/b1kP4/P7/7K w - - acd 33; acs 117; bm Nb4; ce 723; pm Nb4;
pv Nb4 Bxb4 a4 Kxd3 a5 Kd4 a6 Bc5 a7 Bxa7 e7 c5 e8=Q c4 Qxg6 Kc5 Qxh5 Bb6 Kg2 Kc6 Qe8+ Kd6 Qf8+ Kd7 Kf3 Kc6 Qf6+ Kc5 Kf4 Bc7+ Kf5 Bh2 Ke6 d4 Qh4 Bb8 Qe7+ Kc6 Qd7+ Kb6;

r1qn1rk1/p1pp1ppp/1p2p2b/1P2P3/P7/R2B1N2/1P4PP/3Q1R1K w - - acd 33; acs 1965; bm Bxh7+; ce 1067; pm Bxh7+;
pv Bxh7+ Kh8 Bb1 Nc6 bxc6 Kg8 cxd7 Qa6 Nh4 Qc4 Rh3 Rad8 b3 Qc1 Qd3 Qxf1+ Qxf1 Rxd7 Rd3 Rd8 Nf3 Rxd3 Bxd3 Rd5 g3 g6 Be4 Rc5 Qa6 Kg7 Qxa7 Rc3 Kg2 Be3 h4 b5 Qb8 bxa4 bxa4 Rc4 Qa8 Rb4;

r3k2r/bppbqp2/P1np2n1/1B6/3pP1p1/P1P3B1/3N1PPN/R2Q1RK1 b kq - acd 35; acs 900; bm O-O-O; ce 232; pm O-O-O;
pv O-O-O Bxc6;

3r3r/k7/2p5/1pPp1p1p/pP2pPpP/P1K1P1P1/2b5/BN6 w - - acd 61; acs 900; bm Kd4; ce 0; pm Kd4;
pv Kd4 Bxb1 Bb2 Rdf8 Bc1 Bd3 Bd2 Rhg8 Be1 Bc4 Bf2 Rd8 Bg1 Kb7 Bf2 Rg7 Bg1 Rf7 Bf2 Bb3 Be1 Rdd7 Bc3 Rfe7 Bd2 Rc7 Bc3 Bc4 Be1 Rcd7 Bf2 Bb3 Bg1 Re8 Bf2 Rc7 Bg1 Rd8 Bf2 Rdd7 Be1 Ka7 Bc3 Rc8 Bb2 Rg8 Bc3 Re8 Bb2 Kb7 Bc3 Rf7 Bd2 Ree7 Be1 Bc4 Bf2 Rf8 Be1 Rfe8 Bf2 Re6;

8/2pb1k1K/3p2p1/5pP1/2PPpB2/PP6/8/8 b - - acd 74; acs 673; bm e3; c0 "
c6 is fools gold and loses (does not draw): ce -541; pv c6 Bxd6 e3 a4 Ke6 Bg3 Kf7 Kh6 Be6 a5 Bd7 b4 Bc8 Kh7 e2 Bf2 f4 Be1 f3 Bf2 Ke7 Kxg6 Ba6 d5 Bxc4 dxc6 Kd6 Kf6 e1=R Bxe1 Kxc6 g6 Kb7 g7 f2 Bxf2 Ka6 Kf5 Bb3 Ke5 Bg8 Be1 Bc4 Kd4 Bg8 Kc5 Kb7;"; ce 0; pm e3; pv e3 Bxe3 f4 Bxf4 Bf5 a4 Bc2 a5 Bxb3 c5 Bc4 cxd6 cxd6 Bxd6 Ke6 Bc5 Kf7 Kh6 Bd5 Bd6 Bc4 Be5 Bd5 a6 Ba8 a7 Bd5 Bf4 Bg2 Bd2 Be4 Kh7 Bc6 Bb4 Be4 Bd6 Bd5 Bf4 Be4 Bc7 Bd5 Bb6 Be4 Kh8 Bd5 Ba5 Be4 Bc3 Bd5 Bd2 Be4 Ba5 Bd5 Bb6 Be4 Kh7 Bd5 Kh6 Be4 Bd8 Ke8 Bc7 Kf7 Bb8 Bg2 Kh7 Be4 Bf4 Bd5 Be3 Bg2 Bf2 Bd5 Bh4 Be4 Kh6 Bd5 Be1 Bb7 Bb4 Bd5 Bc5 Bc6;
Parent - - By dorszcz (*) Date 2018-11-21 05:38
r1qn1rk1/p1pp1ppp/1p2p2b/1P2P3/P7/R2B1N2/1P4PP/3Q1R1K w - - 0 17

Bhx7 is one option. What's another one?

8/2pb1k1K/3p2p1/5pP1/2PPpB2/PP6/8/8 b - - 0 1

e3 draws.
Parent - - By user923005 (****) [us] Date 2018-11-21 19:11
In regard to : "e3 draws."

If you examine the EPD record carefully, the chosen move is e3.  The stuff about move c6 was a comment field (c0).
I will look to find the other option.
Parent - - By dorszcz (*) Date 2018-11-21 19:54
I see. It was early in the morning and I was in a hurry, that's why I missed it.

The background is (first post order):
-position 1 is from playchess game
-position 4 comes from an old book about tactics I don't know the name, but I remember that the study is from 1911.
-positions 2,3,5 are mine.

Was it too easy or good?
Is acs a time? Does it mean that engine found for example move Bxh7+ in 1965 seconds = 32.75 minutes?
Two positions have acs 900. Is this a coincidence?
Parent - - By user923005 (****) [us] Date 2018-11-21 21:07
I like all of your test problems.
I would classify them as "medium" which is to say about the same difficulty as the Arasan test.
For some really hard problems, try Vincent Lejune's test sets or Walter Eigenmann's test sets.

I think your positions were fun and interesting.
I also made a test set recently, about the same difficulty as yours.  I am still working the bugs out of it.
;-)
It's not as easy as people might think.
Attachment: 100bril.epd - Walter (9k)
Attachment: hard-2018-199.epd - Vincent (15k)
Parent - - By dorszcz (*) Date 2018-11-21 21:45
Yes, I know all Vincent Lejune's and Walter Eigenmann's tests but I prefered to post something that is unknown.
Parent - By user923005 (****) [us] Date 2018-11-21 21:56
I agree that sometimes hard positions which are already know can get recycled into new tests.
Sometimes it is valuable and sometimes it is just a waste of CPU cycles, since you have already analyzed the spots off of those positions.
I always check my database first, to see if I have already analyzed a position.

Arves, Yacpdb, and Pdb are all good places to look for problems.
Also, high end matches like TCEC can produce some wonderful stuff.
Parent - - By dorszcz (*) Date 2018-11-21 21:52
No, this "hard-2018-199.epd - Vincent (15k)" I haven't seen before. The last was 2016 I analyzed. Vincent is Vinvin, right?
Parent - By user923005 (****) [us] Date 2018-11-21 21:54
Yes, Vincent is vinvin
Parent - By user923005 (****) [us] Date 2018-11-21 21:17
The field acs is defined in the PGN standard, in the EPD section:
https://opensource.apple.com/source/Chess/Chess-109.0.3/Documentation/PGN-Standard.txt.auto.html

as follows:
"16.2.5.2: Opcode "acs": analysis count: seconds

The opcode "acs" takes a single non-negative integer operand.  It is used to
represent the number of seconds used for an analysis.  Note that the value may
be quite large for some extended searches and so use of (at least) a long (four
byte) representation is suggested."

It is not the time to solution, it is the time spent analyzing.

The 900 seconds in two of the records is not a coincidence.  I undoubtedly set the time limit to 900 seconds for an analysis session.
Parent - By user923005 (****) [us] Date 2018-11-21 21:01
Re: "Bhx7 is one option. What's another one?"

Bxh7+ is definitely the best move:
r1qn1rk1/p1pp1ppp/1p2p2b/1P2P3/P7/R2B1N2/1P4PP/3Q1R1K w - - acd 40/60;
acs 1612 ; acn 19799132832; ce 1364 ; bm Bxh7+; pv Bxh7+ Kh8 Ng5 Nc6 bxc6 Qd8 Nxf7+ Rxf7 Rxf7 dxc6 Qb1 Qd2 Bg6 Qc1+ Qxc1 Bxc1 Rxc7 Bh6 g4 Rf8 Rf3 Kg8 Bh7+ Kxh7 Rxf8 Be3 Rxc6 b5 h4 bxa4 g5 a3 bxa3 Kg6 Kg2 Kh5 Kg3 Bd2 Rxe6 Be1+ Kh3 Bxh4 Rh8+ Kxg5 Rxh4 Kf5 Ra6 Kg5 Rg4+ Kh5 Kg3 g5 Rxa7;

But Ng5 also wins:
r1qn1rk1/p1pp1ppp/1p2p2b/1P2P3/P7/R2B1N2/1P4PP/3Q1R1K w - - acd 40/70;
acs 1612 ; acn 19799132832; ce 712 ; bm Ng5; pv Ng5 f5 exf6 Bxg5 Bxh7+ Kxh7 Qh5+ Kg8 Qxg5 Rxf6 Rxf6 Nf7 Qg4 Ne5 Qf4 d6 Rg3 Qd7 Qh6 Qe7 Rf4 Rf8 Rxf8+ Qxf8 Qxe6+ Qf7 Qxf7+ Kxf7 Rc3 Ke6 Rxc7 d5 Rxa7 Nc4 b3 d4 Rxg7 Na5 Rg3 Nb7 Rg6+ Kd5 Rxb6 Na5 Rb8 d3 Rd8+ Ke4 Kg1 Nb7 Rd7 Nc5 Re7+ Kd5 Kf1 Kd6 Rg7 Nxb3 Ke1 Nc5 a5;
Up Topic The Rybka Lounge / Test Positions / 5 hard positions

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