White 26

[cheesehead]

I intend that when I post a deadline for us in this thread, I'll subtract two hours, to help me get the time straight. I.e., our next deadline posted here will be (Gekkota move 25 post time) + 166 hours. (That's similar to what I do for almost any appointment: write it on my card and calendar as 15 minutes sooner than it really is.) Or would that mess you guys up more than it's worth?

[cheesehead]

An orderly way to continue now would be to copy over our consolidated analysis for after 25 Ne3, so we could start extending it systematically. - - - If [B]25 ... bxc3 26 bxc3 Nxd4[/B]. Here we must _not_ play 27 cxd4, because of the follow-up 27 ... Bxd4 28 Rc1 Bxc5 29 Rxc4 Bb6 and we're a pawn down, with a pinned knight that prevents Bxh6 (and we must not try 30 Kf1 to relieve the pin because of ... Ba6). If [B]25 ... Nxd4[/B] we similarly must _not_ play 26 cxd4, because of the follow-up 26 ... Bxd4 27 Ne4 Bxb2 28 R-moves c3 and our extra knight has to try coping with the extra three Black pawns -- all passed, two connected. Here's an unorthodox try that fails: If [B]25 ... Nxd4 26 Kf2 (or Kf1)[/B] Now neither 26 ... Ne2 nor 26 ... Nc2 is feasible. But if [b]26 ... Nb3 27 Nxb3 cxb3 we remain a pawn down. Black threatens (speculation) 28 ... bxc3 29 bxc3 b2 30 Rb1 Rb3 31 Nc4 Bxc3 32 Bxc3 Rxc3 33 Nxb2 Rb3. If [b]25 ... Nxd4 26 Ng4 Bg7 27 Bxh6 Bxh6 (not ... Ne2+ 28 Kf2 Nxc3 29 Bxg7 Ncd5 and Black has gotten only one pawn for a piece) 28 Nxh6 bxc3 29 bxc3 Ne2+ 30 Kf2 Nxc3 31 Rc1 Ncd5 32 Rxc4 and material is even. (I have to break now. Should finish copying all previous relevant analysis to this thread.)

[cheesehead]

Let's see whether the formatting works now.

* * *

An orderly way to continue now would be to copy over our consolidated analysis for after 25 Ne3, so we could start extending it systematically.

- - -

If [B]25 ... bxc3 26 bxc3 Nxd4[/B]. Here we must _not_ play 27 cxd4, because of the follow-up 27 ... Bxd4 28 Rc1 Bxc5 29 Rxc4 Bb6 and we're a pawn down, with a pinned knight that prevents Bxh6 (and we must not try 30 Kf1 to relieve the pin because of ... Ba6).

If [B]25 ... Nxd4[/B] we similarly must _not_ play 26 cxd4, because of the follow-up 26 ... Bxd4 27 Ne4 Bxb2 28 R-moves c3 and our extra knight has to try coping with the extra three Black pawns -- all passed, two connected.

Here's an unorthodox try that fails:
If [B]25 ... Nxd4 26 Kf2 (or Kf1)[/B] Now neither 26 ... Ne2 nor 26 ... Nc2 is feasible. But if [B]26 ... Nb3 27 Nxb3 cxb3[/B] we remain a pawn down. Black threatens (speculation) 28 ... bxc3 29 bxc3 b2 30 Rb1 Rb3 31 Nc4 Bxc3 32 Bxc3 Rxc3 33 Nxb2 Rb3.

If [B]25 ... Nxd4 26 Ng4 Bg7 27 Bxh6 Bxh6[/B] (not ... Ne2+ 28 Kf2 Nxc3 29 Bxg7 Ncd5 and Black has gotten only one pawn for a piece) [B]28 Nxh6[/B] and if (speculation) bxc3 29 bxc3 Ne2+ 30 Kf2 Nxc3 31 Rc1 Ncd5 32 Rxc4 and material is even.

(I have to break now. Should finish copying all previous relevant analysis to this thread.)

[WMHalsdorf]

If 25 ... Nxd4 26 Ng4 Bg7 27 Bxh6 Ne2+ 28 Kf2 Bxc3 favors Black.
If 25 ... Nxd4 26 Ne4 appears to favor us.

[cheesehead]

[QUOTE=WMHalsdorf;371028]If 25 ... Nxd4 26 Ng4 Bg7 27 Bxh6 Ne2+ 28 Kf2 Bxc3 favors Black.[/QUOTE]I think you mean:

If 25 ... bxc3 26 bxc3 Nxd4 27 Ng4 Bg7 28 Bxh6 Ne2+ 29 Kf2 Bxc3 favors Black.

... and the point is that 28 Bxh6 is a goose chase that neglects the important area of action, so 27 Ng4 didn't accomplish much.

[cheesehead]

[QUOTE=WMHalsdorf;371028]If 25 ... Nxd4 26 Ne4 appears to favor us.[/QUOTE]Just quick notes:

1) I expect Black to play 25 ... bxc3.

2) After 25 ... bxc3 26 bxc3 Nxd4, how does 27 Ne4 look?

I'll return to analysis soon.

[cheesehead]

So, I logon because I've finished consolidating our analysis for after 25 Ne3, and what do I discover?

[SIZE=3]They played [URL="http://mersenneforum.org/showpost.php?p=371425&postcount=138"]25 ... Bg7?![/URL][/SIZE] without any Ne4 or Ng4 threat by us ??

Our next deadline is, according to the standard rule about the move just made, in the afternoon of April 24 (Hubble Space Telescope's 24th launch anniversary, my 65th birthday anniversary and the 80th anniversary of Shirley MacLaine's [URL="http://www.shirleymaclaine.com/topics/reincar-introduction.php"]most recent birthday[/URL]), but since there's been an epidemic of lateness recently, I'm going to note the deadline time here as 11:08 UTC, as it was for the most recent on-time move.

[cheesehead]

is the consolidated analysis we had previously prepared in the "White 25" thread. (The actual Black move [B]25 ... Bg7[/B] was not considered in any of that, but some of those analyzed lines included ... Bg7 on a later move, so may be of some use.)

[I]If [B]25 ... bxc3 26 bxc3[/B]

[B]26 ... Nxd4[/B] (not 26 ... Rb2 27 Nxc4 Rb8 (not 27 ... Rc2 28 Be4))

[B]27 Ne4[/B] is better. (NOT 27 cxd4 Bxd4 28 Rc1 Bxc5 29 Rxc4 Bb6 and we're a pawn down, with a pinned knight that prevents Bxh6, and we must not try 30 Kf1 to relieve the pin because of ... Ba6
and also NOT 27 Ng4 Bg7 28 Bxh6 Ne2+ 29 Kf2 Bxc3 which favors Black)

[B]27 ... ???[/B] <== needs analysis

[B]27 Nxc4[/B] Ne2+ 28 Kf2 (or Kf1)

28 ... Nxc3
29 Nd6+ (not 29 Bxc3 Bxc3 leaving us a pawn down) <== needs analysis
(NOT 29 ... Kf8 (where Black varies from the main line we've looked at recently) 30 Rc1 Na2 31 Rc4 (NOT 31 Nxc8 Nxc1 which leaves us the Exchange down. E.g., 32 Nxe7 Bxe7 33 Bxc1 Bxc5 (check, if 28 Kf2))
Here we have threats, such as 32 Nxc8 33 Nxe6+ 34 Bd5 or 32 Bxh6 but I don't have time to sort them all out.
I've ruled out some Black possibilities on move 31, but these remain, each with some sort of merit:
31 ... Rb1 (check, if 28 Kf1)
31 ... Rb2
31 ... Rb6
31 ... e5
31 ... Be5
31 ... Bg7
31 ... g5
31 ... h5

28... Bxc3 is better for Black (LaurV) <== needs analysis

-

If [B]25 ... Nxd4[/B]
Our candidates: [strike]26 cxd4[/strike], 26 Ne4, 26 Nxc4, 26 Ng4

[strike]26 cxd4[/strike] Bxd4 27 Ne4 Bxb2 and our extra knight has to try coping with the extra three Black pawns -- all passed, two connected.

[B]26 Ne4[/B] appears to favor us. (WMHalsdorf)

[B]26 Nxc4[/B]. (LaurV) We are still strong in the center, they can't use that horse for nothing, except eventually Ne2+, with the exchange in c3 from which we exit with advantage.

[B]26 Ng4[/B] (NOT Kf2[or Kf1], when neither 26 ... Ne2 nor 26 ... Nc2 is feasible, but if 26 ... Nb3 27 Nxb3 cxb3 we remain a pawn down. Black threatens [speculation] 28 ... bxc3 29 bxc3 b2 30 Rb1 Rb3 31 Nc4 Bxc3 32 Bxc3 Rxc3 33 Nxb2 Rb3.)

[B]26 ... Bg7[/B] 27 Bxh6 Bxh6 (not ... Ne2+ 28 Kf2 Nxc3 29 Bxg7 Ncd5 and Black has gotten only one pawn for a piece) 28 Nxh6 and if [speculation] bxc3 29 bxc3 Ne2+ 30 Kf2 Nxc3 31 Rc1 Ncd5 32 Rxc4 and material is even.[/I]

- - - - -

Our move 26 decision ([B]after the actual Black move [/B][U][B]25 ... Bg7[/B][/U]) deadline is Thursday, April 24 11:08 UTC = 6:08 PM Thai time = 7:08 AM EDT = 6:08 AM CDT

[LaurV]

[QUOTE=cheesehead;371454]So, I logon because I've finished consolidating our analysis for after 25 Ne3, and what do I discover?

[SIZE=3]They played [URL="http://mersenneforum.org/showpost.php?p=371425&postcount=138"]25 ... Bg7?![/URL][/SIZE] without any Ne4 or Ng4 threat by us ??
[/QUOTE]
Yeah, I could not believe it too, I was also looking to that for a while last night (about 2 hours!) with the feeling that they made a mistake. They gave us not only one tempo, but two. But somehow, no matter how I turn it over, we get no material advantage there. We get a very strong position, and black pieces are, like you said sometime in the past, very "unconnected", but we get no additional wood. Maybe they tried to avoid getting into material disadvantage, otherwise I can't explain why they played this move.

If we get the pawn now (I am talking about [B]26 Nxc4[/B]) for free, which I think we must do, nobody stops us, and we have no better move, then after the b-c exchange (or without it, is the same) and Nxd4, [B]Re1![/B] and they must retreat the horse back, otherwise is lost. This is our game (again!) and it seems too easy. Either they did a mistake, or I am missing something.

[QUOTE]
my 65th birthday anniversary[/QUOTE]
Happy and gorgeous birthday, together with all your friends and family!

[cheesehead]

[QUOTE=LaurV;371497]Yeah, I could not believe it too, I was also looking to that for a while last night (about 2 hours!) with the feeling that they made a mistake.[/QUOTE]Or they see something we don't ...

[quote]They gave us not only one tempo, but two. But somehow, no matter how I turn it over, we get no material advantage there.[/quote]We had the chance to nab the h-pawn, but passed it up. :-) I guess they decided not to let us reconsider.

But their dark-square bishop keeps threatening the d4-fork from g7 just as well as it did from f6, and will continue to do so until we move our king, N/c5 or especially our R/a1.

[quote]We get a very strong position, and black pieces are, like you said sometime in the past, very "unconnected",[/quote](More apparent when we contemplated having a rook on the sixth rank.) Actually, all their rank-6 men are protected now. Their only double-duty defender is the N/e7 guarding both c6 and g6.

[quote]but we get no additional wood. Maybe they tried to avoid getting into material disadvantage, otherwise I can't explain why they played this move.[/quote]Maybe they didn't like the complications of the moves we considered most? Anyway, let's just make the best of it.

[quote]If we get the pawn now (I am talking about [B]26 Nxc4[/B]) for free, which I think we must do, nobody stops us, and we have no better move,[/quote]We'll look at the other moves, of course, but Nxc4 is the obvious one.

[quote]then after the b-c exchange (or without it, is the same) and Nxd4, [B]Re1![/B] and they must retreat the horse back, otherwise is lost.[/quote]Let's also examine Rf1 (not Rc1 Ne2+), but not forget Black's prospects on the b-file.

Also, note that after 26 Nxc4 Nxd4 their a-pawn is attacked but unguarded.

[quote]This is our game (again!) and it seems too easy. Either they did a mistake, or I am missing something.[/quote]I think we just have the same positional advantages (especially our outpost knight) we've had for a while, but now with development of our non-advanced knight it's clearer.

[quote]Happy and gorgeous birthday, together with all your friends and family![/quote]Thank you!

- - -

Here, I'm again going to list all our legal moves (striking out the obvious bad ones), which may help us (me, at least) avoid overlooking some possibility:

[B]26 Ra2[/B]

[strike]26 Ra3[/strike] no good reason
[strike]26 Rb1[/strike] bxc3 not good
[B]
26 Rc1[/B]
[B]
26 Rd1[/B]
[B]
26 Re1[/B]
[B]
26 Rf1[/B]

[strike]26 b3[/strike] cxb3 not good
[B]
26 cxb4[/B] ?

[strike]26 Na6[/strike] no good reason
[strike]26 Nb7[/strike] no good reason
[strike]26 Nd7[/strike] no good reason
[strike]26 Nxe6[/strike] no good reason?
[B]
26 Ne4[/B]

[strike]26 Nd3[/strike] no good reason
[strike]26 Nb3[/strike] no good reason
[strike]26 Bc1[/strike] no good reason
[strike]26 Be1[/strike] no good reason
[B]
26 d5[/B]

[strike]26 Nd1[/strike] no good reason
[B]
26 Nc2[/B] ?
[B]
26 Nxc4[/B]

[strike]26 Nd5[/strike] no good reason
[strike]26 Nf5[/strike] no good reason
[B]
26 Ng4[/B]

[strike]26 Nf1[/strike] no good reason
[B]
26 Kf1[/B]
[B]
26 Kf2[/B]

[strike]26 Kh1[/strike] no good reason
[B]
26 Bxc6+[/B]

[strike]26 Bd5[/strike] no good reason
[B]
26 Be4[/B]
[B]
26 Bf1[/B]
[B]
26 Bf3[/B]

[strike]26 Bh1[/strike] no good reason
[B]
26 Bh3[/B]

[strike]26 g4[/strike] no good reason
[strike]26 h3[/strike] no good reason
[strike]26 h4[/strike] no good reason

- - - - -

Taking a break now.

[cheesehead]

[QUOTE=cheesehead;371506][QUOTE=LaurV;371497]Yeah, I could not believe it too, I was also looking to that for a while last night (about 2 hours!) with the feeling that they made a mistake.[/QUOTE]Or they see something we don't ...[/QUOTE]Ah, I think I have it now. They may indeed have seen a threat we had not yet realized we had -- a convergence of force at f8.

Mating threat concept: Suppose they left their B at f6 and we played Nxc4, Bxh6, Nd6+ (forcing ... Kd8), Rf1 (forcing ... Bh8, unless ... Bxd4+ which we meet with cxd4 and rest of plan is undisturbed), Rf8+ (forcing ... Kc7), Bf4, Nb5+ (forcing ... Kb6), then checkmate with Bc7++.

Of course, this leaves out multiple Black moves so couldn't actually happen, but it illustrates the concept.