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Deep Fritz (Computer) vs BlackMamba (Computer)
CCRL 40/40 (2015), rd 14, Dec-20
Queen's Indian Defense: Kasparov-Petrosian Variation. Romanishin Attack (E12)  ·  1-0
ANALYSIS [x]

FEN COPIED

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Kibitzer's Corner
< Earlier Kibitzing  · PAGE 2 OF 2 ·  Later Kibitzing>
Aug-20-17
Premium Chessgames Member
  ChessHigherCat: Here's another variant for you skeptics who are wondering why not 33...cxb5?:

31. Rf7 Qa5 32. Qc4 b5 33. Bxb5 cxb5 34. Nxb5 Bb6 35. Qf4+ Kc8 36. Rc2+ Kd8 37. Qf6+ Re7 38. Qxe7#

Aug-20-17  RandomVisitor: As an experiment I downloaded BlackMamba 2.0 chess engine, which is the version used for this game. I set up the position after 28.Kf1 and let BlackMamba calculate away. This game is a CCRL 40/40 or about 1 minute per move. After 1 minute 16 seconds we have:


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BlackMamba_MP_x64:

<+0.24/24 28...Rdf8> 29.Re2 c5 30.Nd5 Rd8 31.e7

Stockfish immediately rejects 28...Rdf8 as losing. Go figure.

Aug-20-17  thegoldenband: Saw and chose 31. Nd5, but thought the follow-up would be a rook or queen move to the c-file, not a direct exchange sac on c7.
Aug-20-17
Premium Chessgames Member
  diagonalley: i think i'll go back to bed....
Aug-20-17  Walter Glattke: Let us try 31.Rxc7 Kxc7 32.Nb5+ cxb5 33.Rc2+ Kd6 34.Rd2+ Ke5 seems good for black.
Aug-20-17  Autoreparaturwerkbau: Had about two thousand questionmarks above my head watching this game unfold. I can safely go eat my breakfast now.
Aug-20-17
Premium Chessgames Member
  morfishine: Black was snake bit
Aug-20-17
Premium Chessgames Member
  morfishine: <RandomVisitor: 28...Rdf8 has to be one of the biggest mistakes I have seen a computer play> Yes, its a real head scratcher, but computers seem to do that: its either too deep for us to comprehend without a detailed explanation, or the engine has basically thrown in the towel (or perhaps just playing out its last few threats)

*****

Aug-20-17  drollere: greek to me!
Aug-20-17  catlover: Usually when when I don't get a POTD, once I see the game line, I say, "Oh, NOW I see it..."

Alas, I still don't see it.

Aug-20-17
Premium Chessgames Member
  botvinnik64: Looks like something from an Ivanchuk game!
Aug-20-17
Premium Chessgames Member
  Jimfromprovidence: I saw 31 Nd5 (seeing 32 Nxc7) cxd5 32 Rxc7 Qf4 (to prevent 33 Qg3+ and attack the rook).


click for larger view

Don't know what comes next.

Aug-20-17
Premium Chessgames Member
  tamar: BlackMamba ended up taking a wild off-balance shot falling out of bounds that clanked off the rim.
Aug-20-17
Premium Chessgames Member
  cormier:


click for larger view

Analysis by Houdini: d 24 dpa only

1. ⩲ (0.26): 28...Rde8 29.Rd7 Rhf8 30.Rf7 Rxf7 31.exf7 Rxe1+ 32.Kxe1 Bd6 33.Bc4 Kc7 34.Nd1 Qe4+ 35.Ne3 Bf8 36.Kf1 Bb7 37.Qc3 Bc8 38.Qh8 Qe7 39.Qg8 h5 40.g3 a5 41.a4 Qd6 42.Qh8 Qh6 43.Qe5+ Kb7 44.Qe8 Kc7 45.Kg2 Qd6

2. ⩲ (0.46): 28...Be5 29.Rxd8+ Rxd8 30.Ne4 Re8 31.Bc4 Bb7 32.Qd1 g3 33.Qd7 Qf8 34.Re2 Qe7 35.Nxg3 Bxg3 36.fxg3 Qxd7 37.exd7 Rf8+ 38.Ke1 Rd8 39.Re6 h5 40.Re8 Kc7 41.Rxd8 Kxd8 42.Kf2 a5 43.Be2 Kxd7 44.Bxh5 Ke6 45.Bf3 Ke5 46.Ke3 Kf5 47.g4+ Kg5

Aug-20-17
Premium Chessgames Member
  agb2002: White has a bishop and a knight for the bishop pair.

White can weaken the diagonal b8-h2 with 31.Rxc7 but after 31... Kxc7 32.Nb5+ cxb5 I don't know how to resume the attack.

That's all I can do today.

Aug-20-17
Premium Chessgames Member
  chrisowen: Rofls d5s doubts vints rinks hide-and-seeks vides hunks h5s huffon o e1s v et co d5s dunkus c7s clunghug u h2s hub f7s flunghug bunks h5s hogsus bud it's ford 34...d4 vet jo v duddy 1 ousts conts vim it's ford 34...g3 vet jo v guns 1 ousts conts vim minds vow finest vivas vow bonds 35.Qb4 ado bonds hum blobb 35.Bb5 ado u bondus 2 ousts conts vim aider 35.Qa4 ado ables 2 3 ousts cots vim clunk 35...Rc8 v eyeball churchmen lug dints 35...d4 v eye o duddy 1 ousts conts vim dunkus 36.Kd2 add dub big clungs;

36...Bc6 v elm oh cutoffs bud clung 36...Rc5 bend o clungs 5 ousts conts vim gunghos;

37.g3 nah gunsy bud avowsus 37...Ka8 v eel etc o ashyfaces bud mates 4 ave bud honeyon;

37...Qh1 reels vet ho 11 12 ousts conts vim bud evermore 38.Qe7 obvious eggshead bud dunkhung 38...Bd7 veg o bud dunklugs bud mates 3 ave rofls flaps paw abc would i hdq dumbs ms hoggy v tonks u vided it's vasts i wents ya it's vasts win yates easts winys vivas flavs yeast win oh aye twins antis yew twains vis ye wains yet twain yes waist yen way inset d5s dockus lug ave i rofls flaps lip paw bawls wap abc w chug fleed it's vasts i wents ya von guv would bic vim wibble bucks cinch quosh hud dumbs mud ms guy viktor guild ko ok von guv tn u not tonk u vided it's vasts i wents ya von guv would bud u 31.Nd5 bad bod bud ludgate thens dulls flavs vivas loads axe ave thens dabble lands a blows d5s dontus knows win u d5s doffus dutchy dullon doubts dinkus hod hud dutch dog dug gulch ghost ghoul hod hud hug hungs hog divide intos fifths vow vim decide thens dearie me deepin bug u Qh5 32.Ke1 cxd5 33.Rxe7 Qh2 34.Rf7 h5 hogsus bud it's ford 34...d4 vet jo v duddy overts 1 ousts conts vim it's ford 34...g3 vet jo v guns 1 ousts conts vim minds vow finest vivas vow bonds 35.Qb4 ado bonds hum blobb 35.Bb5 ado u bondus 2 ousts conts vim aider 35.Qa4 ado ables 2 3 ousts conts vim clunk 35...Rc8 v eyeball churchmen lug dints 35...d4 v eye o duddy 1 ousts conts vim dunkus 36.Kd2 add dub big clungs 36...Bc6 v elm oh cutoffs bud clungs 36...Rc5 bend o clungs 5 ousts conts vim gunghos 37.g3 nah gunsy bud avowsus 37...Ka8 v eel etc o ashyfaces bud mates 4 ave bud honeyon 37...Qh1 reel vet ho 11 12 ousts conts vim bud evermore 38.Qe7 Bd7 veg o bud dunklugs bud mates 3 ave duffs doffs bombs bum flubb fob mod dom dumbguy mud muffs mofty mob vim cc rump willow-up vet vow but tubby buntin tobys jug blunt trouble von guv huffs flush hud hod cod cud clods chods dutch treat i vet us ums coils gives eh flubb cinch ducks big coils vim either hints rinks ave rofls d5s dockus;

Aug-20-17  Bluegrey: This is definitely not a human puzzle.
Aug-20-17  devere: 31.Nd5 cxd5 32.Rxc7 Kxc7 33.Qg3+ Kc6 34.Bd3, and the threat of Rc2+ is decisive.


click for larger view

It's really quite a nice combination, even though a computer found it.

Aug-20-17
Premium Chessgames Member
  patzer2: Even for a computer program, 24...Bc7 allowing 25. Rcd1 ⩲ to = seems a bit too passive.

Instead, my computer indicates Black can attain full equality and a fairly quick draw by opening things up with 24...c5 25.dxc5 Bxc5 26.Ne4 Bd4 27.Nc5 Bxf2+! 28.Kxf2 Qd2+ 29.Be2! Qd4+ 30.Kg3 Qe5+ 31.Kf2 Qd4+ = (0.00 @ 40 depth Stockfish 8.)

Aug-20-17
Premium Chessgames Member
  chrisowen: Death leader!
Aug-20-17  izimbra: <Bluegrey: This is definitely not a human puzzle.> <devere: 31.Nd5 cxd5 32.Rxc7 Kxc7 33.Qg3+ Kc6 34.Bd3, and the threat of Rc2+ is decisive. It's really quite a nice combination, even though a computer found it.>

It is very hard to see - if two unforced sacrifices are accepted, then the Black K has no safe squares. But it turns out that Black has no good K defense even when the R sacrifice is not accepted. and the N capture is deferred. The computer evaluations of Black's position should have penalized B more for the Bishop on A8, where it can't attack or defend well, but still takes up space around the Black K.

Aug-20-17  RandomVisitor: After 28.Kf1 black appears to have a drawing line


click for larger view

Stockfish_17081914_x64_modern: <6 hours 20 minutes computer time, 8 cores>

<+0.07/50 28...Be5 29.Rxd8+ Rxd8 30.Ne4 Bb7> 31.Bd3 Qf8 32.Qc2 Bc8 33.Ng5 hxg5 34.Rxe5 Qf6 35.e7 Re8 36.Qe2 g3 37.Qe3 gxf2 38.Qxg5 Qxg5 39.Rxg5 Rxe7 40.Kxf2 Kc7 41.g4 c5 42.Rg6 Be6 43.Kg3 Bd5 44.Kf4 c4 45.Bf5 Re2 46.Rh6 Rxb2 47.Ke5 Bg2 48.Rh7+ Kc6 49.Kd4 Rd2+ 50.Kxc4 a5 51.Rh6+ Kc7 52.g5 b5+ 53.Kb3 Bc6 54.Rf6 Rf2 55.Bd3 Rg2 56.g6 Rg3 57.Kc2 b4 58.axb4

+0.92/50 28...Rde8 29.Rd7 Rhf8 30.Re2 Bc7 31.g3 c5 32.Rf7 Qh5 33.Ke1 Rd8 34.Re3 Qh1+ 35.Bf1 Bg2 36.Qc4 Rc8 37.Rxf8 Rxf8 38.e7 Re8 39.Qb5 Qxf1+ 40.Qxf1 Bxf1 41.Kxf1 Kc8 42.Nd5 Bd6 43.Re6 Kd7 44.Rxh6 Bxe7 45.Rg6 Rh8 46.Rg7 Rh1+ 47.Ke2 Ke6 48.Nxe7 Kf6 49.Rxg4 Kxe7 50.Rg7+ Kf6 51.Rd7 Rb1 52.Rd2 Ke5 53.Ke3 c4 54.f3 Re1+ 55.Kf2 Ra1 56.Re2+ Kf6 57.Rc2 b5 58.g4 a5 59.f4 Rb1 60.Kf3 Rg1 61.Re2 Rf1+ 62.Ke4

+1.41/50 28...g3 29.Rxd8+ Rxd8 30.Re2 gxf2 31.e7 Re8 32.Qe6 Qxe6 33.Rxe6 Kc7 34.Nd5+ Kd7 35.Rxh6 Be5 36.Bd3 cxd5 37.Bb5+ Kxe7 38.Bxe8 Bxb2 39.Bb5 Bg7 40.Rh7 Kf8 41.Kxf2 d4 42.Rh5 Be4 43.g4 Kf7 44.Bc4+ Kf6 45.Ke2 Bf8 46.a4 Bc2 47.g5+ Kg6 48.Rh8 Be7 49.Bd3+ Bxd3+ 50.Kxd3 Kxg5 51.Ra8 a5 52.Kxd4 Kf5 53.Kd5 Bc5 54.Re8 Kf4 55.Re6 Kg5 56.Ke5 Bf2 57.Re8 Kg4 58.Kd5 Kf3 59.Kc6 Bc5 60.Re5 Kf4 61.Rd5

+3.32/49 28...Rxd1 29.Nxd1 Bd6 30.Ne3 Qf4 31.Qc4 Qxc4+ 32.Bxc4 c5 33.Nf5 Bf4 34.e7 Bc6 35.Bf7 Bb5+ 36.Kg1 Bd2 37.e8Q+ Bxe8 38.Rxe8+ Rxe8 39.Bxe8 c4 40.Ne3 g3 41.Nxc4 Bf4 42.Kf1 Kc7 43.fxg3 Bxg3 44.Ke2 a6 45.a4 a5 46.Kf3 Bh4 47.Ne3 Bg5 48.Nd5+ Kd6 49.Nxb6 Kc5 50.Nd7+ Kb4 51.Ne5 Bf6 52.Nd3+ Kb3 53.Kg4 Bg5 54.g3 Kc2 55.Bb5 Kb3 56.Kf5 Bd8 57.Kg6 Bg5 58.Bc6 Kc4 59.Be4

Aug-21-17
Premium Chessgames Member
  TheAlchemist: I guess playing against the White Mamba would have been unfair.
Aug-23-17
Premium Chessgames Member
  AylerKupp: <<RandomVisitor> Stockfish immediately rejects 28...Rdf8 as losing. Go figure.> part 1 of 2)

That might be Stockfish 8's assessment, although with an eval of [+0.74] I would classify it as "White stands slightly better" rather than "White is winning". But other engines don't qualitatively agree with Stockfish, considering 28...Rde8 and 28...Be5 to result in an equal position.

I had Houdini 4 and Komodo 11 analyze the same position for about 2.5 minutes, along with Black Mamba 2.0 and Stockfish 8. 2.5 minutes was still within a reasonable time for one move under game circumstances, particularly since I'm still stuck with an old Intel 32-bit, 4 core system. And that was a time when all 4 engines completed a full search at a given depth. And I should note, as I'm sure you found out, that Black Mamba 2.0 only allows the specification of MPV=1 even though my GUI (Arena 3.5) allows the specification of MPV=3. But, in that case, Black Mamba does not display any evaluations until you stop the analysis, and then it only gives the evaluation of the best move found at that search depth.

At any rate, here are the evaluations of Black's choices after 28.Kf1, listed in ascending order of the average evaluations, after about 2.5 minutes of calculation:


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Black's BMamba 2.0 Houdini 4 Komodo 11 Stockfish 8

Move d=20 d=21 d=24 d=29

(time) 00:02:32 00:02:24 00:02:41 00:02:28 <Avg>

---------- ---------- ---------- ----------- ---------- ----------

28...Be5 [------] [0.00] [+0.60] [+0.00] <[+0.20]>

28...c5 [------] [+0.31] [------] [------] <[+0.31]>

28...Rde8 [+0.26] [0.00] [+0.37] [+0.74] <[+0.34]>

28...Rdf8 [------] [------] [+0.43] [------] <[+0.43]>

28...g3 [------] [------] [------] [+0.97] <[+0.97]>

When calculating the average evaluations the evaluations of those moves not reported by the engines as one of their top 3 moves (top move in the case of Black Mamba) are considered to be null. And in this case Houdini's and Komodo's evaluation of 28...Rde8 was closer to Black Mamba's than Stockfish's.

Better averages as well as Rating Adjusted Averages (RAdjAvg) can be calculated if each null move is replaced with an evaluation one centipawn less than the move with the lowest evaluation by that engine. This is typically the best evaluation that the move could receive from the engine and therefore the average evaluations will likely be optimistic since the engine's actual evaluation of the move could be much lower. Then a Rating Adjusted (weighted) average can be calculated using the CCRL 40/40 ratings for each engine.

Black's BMamba 2.0 Houdini 4 Komodo 11 Stockfish 8

Move d=20 d=21 d=24 d=29

(time) 00:02:32 00:02:24 00:02:41 00:02:28

(rating) 3132 3252 3394 3391 <Avg> <RAdjAvg>

---------- ---------- ---------- ----------- ---------- ---------- ----------

28...Be5 [+0.27] [0.00] [+0.60] [+0.00] <[+0.22]> <[+0.23]>

28...Rde8 [+0.26] [0.00] [+0.37] [+0.74] <[+0.34]> <[+0.40]>

28...Rdf8 [+0.27] [+0.32] [+0.43] [+0.98] <[+0.50]> <[+0.57]>

28...c5 [+0.27] [+0.31] [+0.61] [+0.98] <[+0.54]> <[+0.63]>

28...g3 [+0.27] [+0.32] [+0.61] [+0.97] <[+0.54]> <[+0.63]>

And here is a summary of how the 4 engines ranked the moves, without regard for the value of the evaluation, listed in ascending average rank order..

Black's BMamba 2.0 Houdini 4 Komodo 11 Stockfish 8

Move d=20 d=21 d=24 d=29

(time) 00:02:32 00:02:24 00:02:41 00:02:28 <Avg> <TrueRank>

---------- ---------- ---------- ----------- ---------- ---------- ----------

28...Be5 1 1 1 2 <1.3> <1>

28...Rdf8 2 1 3 1 <1.8> <2>

28...c5 2 4 2 4 <3.0> <3>

28...g3 2 4 4 3 <3.3> <3>

28...Rde8 2 3 4 4 <3.3> <3>

True Rank: 1 = [ 28...Be5 ]; 2 = [ 28...Rdf8 ]; 3 = [ 38...c5, 28...g3, 28...Rde8 ]

Aug-23-17
Premium Chessgames Member
  AylerKupp: <<RandomVisitor> Stockfish immediately rejects 28...Rdf8 as losing. Go figure.> part 2 of 2)

I also thought that it would be interested to let each of the engines analyze much longer as would be typical in analysis situations to try to find out which move was actually considered to be the best by the engines when given more time to calculate. The actual time I used was driven by Komodo 11 which took 00:32:30 to reach d=29 and 04:30:25 (almost 4 hours more!) to reach d=30. And the evaluations did not change substantially. Go figure. :-)

At any rate, here are the evaluations of Black's choices after 28.Kf1, listed in ascending order of the average evaluations, after about 4.5 hours of calculation:


click for larger view

Black's BMamba 2.0 Houdini 4 Komodo 11 Stockfish 8

Move d=31 d=30 d=30 d=45

(time) 04:38:52 04:02:56 04:30:25 04:39:57 <Avg>

---------- ---------- ---------- ----------- ---------- ----------

28...Be5 [+0.14] [0.00] [+0.09] [+0.00] <[+0.06]>

28...Rde8 [------] [+0.37] [+0.37] [+0.74] <[+0.49]>

28...c5 [------] [------] [+0.65] [------] <[+0.65]>

28...g3 [------] [+1.42] [------] [+0.97] <[+1.20]>

Now 38...Be5 is clearly seen as being Black's best chance for equality, although 28...Rde8 is still considered by Houdini and Komodo to lead to an equal position. Stockfish still maintains that after 28...Rde8 the position favors White slightly.

Here are the improved average calculations when each null move is replaced with an evaluation one centipawn less than the move with the lowest evaluation by that engine, listed in ascending Rating Adjusted Average based on the latest CCRL 40/40 ratings:

Black's BMamba 2.0 Houdini 4 Komodo 11 Stockfish 8

Move d=20 d=21 d=24 d=29

(time) 04:38:52 04:02:56 04:30:25 04:39:57 <Avg> <RAdj.Avg>

---------- ---------- ---------- ----------- ---------- ---------- -------------

28...Be5 [+0.14] [0.00] [+0.09] [+0.00] <[+0.06]> <[+0.04]>

28...Rde8 [+0.15] [+0.37] [+0.37] [+0.74] <[+0.41]> <[+0.47]>

28...c5 [+0.15] [+1.43] [+0.65] [+0.98] <[+0.80]> <[+0.88]>

28...g3 [+0.15] [+1.42] [-+0.66] [+0.97] <[+0.80]> <[+0.88]>

And here is a summary of how the 4 engines ranked the moves, without regard for the value of the evaluation, listed in ascending average rank order..

Black's BMamba 2.0 Houdini 4 Komodo 11 Stockfish 8

Move d=20 d=21 d=24 d=29

(time) 04:38:52 04:02:56 04:30:25 04:39:57 <Avg> < TrueRank >

---------- ---------- ----------- ---------- ---------- ---------- -----------

28...Be5 1 1 1 1 <1.0> <1>

28...Rdf8 2 2 2 2 <2.0> <2>

28...g3 2 4 4 3 <3.0> <3>

28...c5 2 4 3 4 <3.3> <3>

True Rank: 1 = [ 28...Be5 ]; 2 = [ 28...Rdf8 ]; 3 = [ 38...c5, 28...g3 ]

So after 2.5 minutes of calculation Black Mamba got it wrong as far as what Black's best response to 28.Kf1 should be, not evaluating 28...Be5 to be Black's top move until d=25 and 25 minutes of calculation on my machine. But at least it eventually got it right. And none of the engines considered 28...Rde8 to be Black's losing move, even after about 4.5 hours of calculation.

Perhaps in the future you might hesitate before you ask anyone to "go figure". After all, I might read the request. :-)

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