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Old 2014-06-19, 12:49   #1
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Default White 33

The Gekkota have replied promptly, with [url=http://www.mersenneforum.org/showpost.php?p=376198&postcount=153]32...Kd7[/url] at 19 Jun 14, 10:31.

Our deadline (with one-hour margin) is Thursday, June 26 at 9:31 GMT
= Thursday, June 26 at 16:31 Thai time
= Thursday, June 26 at 5:31 EDT
= Thursday, June 26 at 4:31 CDT
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Old 2014-06-19, 12:59   #2
LaurV
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[edit, huh, you were exactly 1 minute faster, and we ended up with two threads for move 33, and I wasted 10 minutes to see how do I merge them. I succeeded now to delete the other, this is what it was posted in it]

They were fair, played the forced move instant. I would say to play 33 Nb5 and let them have at it over the weekend... Anyhow I am not at home this weekend to do any analyze.
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Old 2014-06-19, 13:18   #3
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Here's part of the consolidated move analysis that I've double-checked (which is not to say that you guys could not find a mistake). I am pleased to show that in this part (33 ... Kxe6) of the move-tree, we have a forced win of either the a5-pawn or a piece, except that there is one branch at move 38 that I haven't finished.

(I'll be posting the NOT YET DOUBLE-CHECKED parts as soon as I've finished them.)

If [B]33 Nxc8[/B]

If [B]33 ... Nxc8 34 Bh3[/B]
If [B]34 ... [/B] (THIS PORTION IS NOT YET DOUBLE-CHECKED)

If [B]33 ... Kxe6[/B].
We can pin the N/e7 to Black's king, then use that to pull his B away from a5-defending duty long enough to nab the a-pawn. That requires persuading Black to move his king to f7, [I]while always being on guard not to allow Black to skewer our K and R with his B.[/I] (Moving our K off the a7-g1 diagonal would be a good way to avoid the skewer, but it'll be tough to find a place where we can afford to spend that tempo while maintaining the pin.)

[B]34 Bh3+[/B] gives our king another flight square in case of (or to avoid) future check from Bd4+ or Bc5+, _and_ reduces the number of squares from which the Black king can defend the N/e7.

If [B]34 ... Kf6[/B] (or ... Kf7 35 Rb7) [B]35 Rb6+ Kf7 36 Rb7[/B]. [I](Note that we place our rook on the a7-g1 diagonal _only_ when giving check, allowing Black no chance to skewer)[/I] Now the N/e7 is both pinned and double-attacked, forcing Black to use his B to defend it.

[B]36 ... Bb4 (or Bf7) 37 Nxe7 Bxe7[/B]. Now we've (1) pulled the B off a5-defending duty and (2) pinned it to the king, allowing us to put our rook on the a7-g1 diagonal without immediate skewer.

[B]38 Ra7[/B] threatens 39 Rxa5, [I]but the R is now on the same diagonal as our K, so before Black's B can move again, we must remember to move our K or R[/I].
Black can protect a5 with his N from b3 or c4, so we have to devise a way to drive it away from those two positions.

If [B]38 ... Nb3 39 [/B] (THIS BRANCH IS NOT YET DOUBLE-CHECKED, though I expect it also to result in our capture of either the a5-pawn or a piece)

If [B]38 ... Nc4 39 Bf1[/B] chases the knight away from a5-guard duty, but not before possible complications if Black un-pins his B.

If [B]39 ... Ke8 or Kf6 or Kf8 (not ... Ke6 40 Bxc4+)[/B] threatens the ... Bxc5+ skewer. but we now have just one tempo for moving our king because Black can't defend both of our attack targets (a5 and c4) with one move.
[B]40 Kg2[/B]. Next we will soon capture one of our targets - but only after complications in one case.

If [B]40 ... any K-move or pawn-move 41 Bxc4[/B]
If [B]40 ... Bc5 41 Ra8+ (or Ra6+) K-moves 42 Bxc4[/B]
If [B]40 ... any B-move except Bc5 41 Bxc4[/B]
If [B]40 ... any N-move except Nf3+ 41 Rxa5[/B]

If [B]40 ... Ne3+[/B] Black complicates, but as far as I've analyzed none can harm us, and we will eventually succeed in capturing at least one of our targets on a5 and c4.

[B]41 Kf2[/B]. We can place our king back on the dark diagonal because it's shielded by the N/e3 from a check via ... Bc5.

If [B]41 ... Bc5 42 Rxa5[/B]. We can nab the pawn here because [I](rather amazingly) [U]none[/U] of the eight possible discovered checks from 42 ... N-move can harm us![/I]
If [B]42 ... Nc2+ 43 Rxc5[/B]
If [B]42 ... Nc4+ 43 Rxc5[/B]
If [B]42 ... Nd1+ 43 Kf3[/B]
If [B]42 ... Nd5+ 43 Rxc5[/B]
If [B]42 ... Nxf1+ 43 Kxf1[/B] (not 43 Rxc5 Nxh2)
If [B]42 ... Nf5+ 43 Rxc5[/B]
If [B]42 ... Ng2+ 43 Rxc5[/B]
If [B]42 ... Ng4+ 43 Ke2[/B] If [B]43 ... Nxh2 44 Rxc5[/B]

If [B]41 ... Nxf1 42 Kxf1[/B]
If [B]42 ... Bb4[/B]
Now Black has made it necessary for our king to travel to assist our rook if we want to capture the a-pawn. But if we were to do just exactly that, Black's king might travel down to take our g&h pawns and then march his g&h passers down to victory.

(I'm not going to try counting moves _now_ to see whether we could win a king/pawn-race, but we can do that later if this position does arise.)

By themselves the Black a-pawn and B/b4 pose no offensive threat. Our a-pawn can continue to block theirs by itself (as long as we prevent Black's king from reaching it), while we switch our rook to the king-side.

If [b]33 Nb5[/b] -- THIS PART NOT YET FINISHED

Last fiddled with by cheesehead on 2014-06-19 at 13:29
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Old 2014-06-19, 13:27   #4
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[QUOTE=LaurV;376213]I would say to play 33 Nb5 and let them have at it over the weekend... Anyhow I am not at home this weekend to do any analyze.[/QUOTE]Oh, so we were NOT yet agreed on our move 33. More analysis to do.

- -

Last fiddled with by cheesehead on 2014-06-19 at 14:06
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Old 2014-06-19, 20:53   #5
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When I proposed 33 Nb5, it was just a let's-look-at-this-alternative-idea-to-see-whether-it-has-any-merit. I had _not_ seriously analyzed it. I'd just taken a casual look.

Now that I've looked longer at it ... [I]33 Nb5 turns out to be a [U]terrible[/U] move in this position.[/I]

[QUOTE=LaurV;376213]I would say to play 33 Nb5 and let them have at it over the weekend[/QUOTE]They would quickly find what I did --- [I]that after 33 Nb5 [B]Be5[/B] Black would destroy our advantage![/I]

33 Nb5 Be5

Our rook and knight/e6 are both attacked. There's only one rook move that protects the N/e6:

34 Rb6

Then Black brings back his N/d2 to attack our rook again:

34 ... Nc4

Now, our rook has no other safe square to go to. It can be captured on any square it can move to, as well as be captured where it sits.

This line (33 Nb5) is busted!

(See what I meant earlier about Black having plenty of fight left, if we made any mistake?)

[quote]... Anyhow I am not at home this weekend to do any analyze.[/quote]Okay, but [U]DO NOT POST 33 Nb5[/U]

- - - -

Vote:

33 Nxc8 -- 5

33 Nb5 -- [strike]minus infinity[/strike] 0

Last fiddled with by cheesehead on 2014-06-19 at 21:23
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Old 2014-06-20, 02:51   #6
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[QUOTE=cheesehead;376214]< snip >

If [B]33 Nxc8[/B]

If [B]33 ... Nxc8 [/B][strike][B]34 Bh3[/B]
If [B]34 ...[/B] (THIS PORTION IS NOT YET DOUBLE-CHECKED)[/strike]

< snip >
[/QUOTE]There's a different move 34 for us that's superior to 34 Bh3 here:

If [B]33 ... Nxc8 [U]34 Bc6+[/U][/B] Not a sacrifice (it's just deflect-the-defender), but pretty anyway -- it forces either one or two piece trade-downs.

If [B]34 ... Kxe6 35 Rxc8[/B] threatening [B]36 B-moves[/B] and [B]37 Rxc3[/B]. Even if only one piece-trade, this increases the relative value of our material advantage.
If [B]34 ... Kxc6 35 Rxc8+[/B] and [B]36 Rxc3[/B] with two trade-downs of pieces. Then, with all bishops off the board, we really get to show our rook's superiority over Black's remaining knight as we clean away all of Black's counter-chances.

- - -

Just to be formal about it:
[QUOTE]
If [B]33 Nb5[/B] -- [strike]THIS PART NOT YET FINISHED[/strike][/QUOTE][B]33 Nb5[/B] -- turns out to be no good because Black has a real zinger of a reply:

If [B] 33 ... Be5[/B] Black now attacks both our rook and N/e6. We have only one move that both saves the rook and protects the N/e6:

[B]34 Rb6[/B]

But then Black brings back his N/d2 to attack our rook again:

[B]34 ... Nc4[/B]

Now, our rook has no safe square -- it can be captured on any square it can move to, as well as be captured where it sits.

So, this line ([B]33 Nb5[/B]) for us is busted!

- - -

Now, there's just one more incomplete analysis branch ([B]38 ... Nb3 39[/B] ???, after [B]38 Ra7[/B], in the [B]33 ... Kxe6[/B] line) to finish off, to demonstrate the superiority of [B]33 Nxc8[/B] (and let us coast for a few moves on our already-done analysis).

Last fiddled with by cheesehead on 2014-06-20 at 03:11
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Old 2014-06-20, 05:42   #7
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What's wrong with 33 Nb5 Be5 ???
I had a look to it before last moves, when it was proposed and it came to discussion, I though that is why we moved the horse (!) there is nothing better we can do now. After 34 Nc5 Kd8 (or Ke8, no other move for black, both bad, as they link the bishop and containts the king on the last line) 35 Ra8 Nc4 (if they don't defend that pawn, we make a free pawn and win) 36 Bb7 ... etc, nothing is better than that! We still keep all the advantage, position and pieces, black has no moves after it.

However, I will look better to both 33 Nb5 and 33 Nxc8, maybe you see something I don't...

Last fiddled with by LaurV on 2014-06-20 at 05:43
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Old 2014-06-20, 08:10   #8
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[QUOTE=LaurV;376286]What's wrong with 33 Nb5 Be5 ???[/QUOTE]When I analyzed it before my last post, I found that in every case we lose our rook for a knight or bishop, and material is back to even. That's why I said it was busted.

So now I looked again.

[B]33 Nb5 [/B][B]Be5[/B] Black now attacks both our rook and N/e6.
If [B]34 Rb6[/B] to try to save both, then Black plays [B]34 ... Nc4[/B].
At this point, our rook is threatened with capture on any square it can move to.
However, [I]I didn't see some possibilities before.[/I]

If [B]35 Nc5+[/B] Black must move his king now instead of taking our rook.
If [B]35 ... Kd8 36 Nb7+ Kd7 37 Ra6[/B] our rook is temporarily safe but our N/b7 is pinned.
If [B]35 ... Ke8 36 Nd6+ Bxd6 37 Rb3 or Rb1 Bxc5+ 38 Kf1[/B] and now we're down a bishop and [I]two[/I] knights for a rook.

Neither of those end positions is as good as we can get with 33 Nxc8.

Last fiddled with by cheesehead on 2014-06-20 at 08:16
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Old 2014-06-20, 09:50   #9
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Well... I still don't know why you want to move 34 Rb6. The rook is good there on the last line, keeping the bishop still on c8. Did you read my post?

In fact, I said before that we won this game, and now, this is how we win the game: 33 Nb5 Be5 34 Nc5 Kd8 35 Ra8 Nc4 36 Bb7 Nb6 38 Rxa5 Bxb7 38 Nxb7+ Kd7 39 Ra6 Nec8 40 a5 Kc6 41 Nb7d6 Nxd6 42 Rxb6 Kd7 43 a6 Nxb5 44 Rxb5 Bd4 45 Kg2 Kc6 46 Rb7. Clear white win and black can't do nothing against.

[I mean, Nxc8 might have its merits, but giving minus infinite to Nb5 is not very... orthodox either, on your side]

Last fiddled with by LaurV on 2014-06-20 at 09:56
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Old 2014-06-20, 17:44   #10
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[QUOTE=LaurV;376292]Did you read my post?[/QUOTE]Yes, but it seemed that some moves were missing.

[quote]33 Nb5 Be5 34 Nc5 Kd8 35 Ra8 Nc4 36 Bb7 Nb6 [strike]38[/strike]37 Rxa5 Bxb7 38 Nxb7+ Kd7 39 Ra6 Nec8 40 a5 Kc6 41 Nb7d6 Nxd6 42 Rxb6 Kd7 43 a6 Nxb5 44 Rxb5 Bd4 45 Kg2 Kc6 46 Rb7.[/quote]That's far more complete than you previously posted -- but you don't show how any alternative moves are refuted!!

Let's go through with comments:

[B]33 Nb5 Be5 34 Nc5[/B] For some reason I overlooked 34 Nc5+ before, which is why I thought Rb6 was required to save the knight.
[B]
34 ... Kd8
[/B]
What if 34 ... Ke8 ?[B]

35 Ra8 Nc4 36 Bb7 Nb6 37 Rxa5 Bxb7
[/B]
What about alternatives for Black on move 37?[B]

38 Nxb7+ Kd7
[/B]
What if 38 ... Ke8 ?
[B]
39 Ra6 Nec8[/B]

What if 39 ... Nbc8 or Nbd5 or Ned5 ?
[B]
40 a5 Kc6
[/B]
What if 40 ... Nd5 ?
[B]
41 Nb7d6 Nxd6
[/B]
What if 41 ... Bxd6 ?
[B]
42 Rxb6 Kd7 43 a6 Nxb5[/B]

What if 43 ... Nc8 ?
[B]
44 Rxb5 Bd4 45 Kg2 Kc6 46 Rb7
[/B]
Our win is not yet clear in that final position.

Suppose 46 ... Bb6
If 47 a7 Kxb7 48 ????
If 47 Rb8
If 47 ... Kc7 48 ????
If 47 ... Ba7 48 ????

[quote][I mean, Nxc8 might have its merits,[/quote][B]33 Nxc8[/B] is a sure win, _by force_, that's simpler than the 33 Nb5 line. In my analysis, I show why Black moves are forced, because any alternative by Black loses faster.

Look at all the questions I raise in the 33 Nb5 line because they might spoil our win! If any of those alternatives works for Black, then 33 Nb5 is not a win _by force_, like 33 Nxc8 is. In fact, if any of those alternatives for Black is sufficiently good, Black might force a draw.

[quote]but giving minus infinite to Nb5[/quote]I apologize for the "minus infinity". I shouldn't have written that.

Last fiddled with by cheesehead on 2014-06-20 at 18:01
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Old 2014-06-20, 18:27   #11
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After i spent one more hour in front of the board (1:05 AM here), it seems we also win with 33 Nxc8 Kxe6 (other moves seems worse for black) 34 Bh3 Kf7 35 Rb7, Bb4 etc, so it seems you are right, in this point does not really matter. However, this seems a bit more complicate for me, it is not "straight by force".

Also 33 Rb6 is winning move. They can't do too much now, and we have a big advantage with the rook and future free pawn there, they have to give a piece for it. If they take the horse 33...Kxe6 then 34 Bh3.

All the trick is that they can't defend the pawn and attack our pawn in the same time without losing a lot of moves.

When I posted today (the "long" branch) I didn't have a board in front of me (job, lunch break), beside of Serge's board, and I may (intentionally) missed to post "branches", but either way, 34...Ke8 seems easier (they let the bishop unattended, however we can't capture it immediately, but we will, eventually, for free). Heavier it may be if they play directly 34...Kxe6, but that is contained too. Out main goal here is not to exchange pieces, but to make that pawn free. (1:25 AM here now, good night! :smile:)

(i keep telling you the time so you won't blame me hard if I say something stupid, I should be sound sleeping at this "early" hour)
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